The key here is to ALWAYS disconnect the car battery before doing any electrical work. Mostly if working with the ECM, because the battery is in the path of the ECM’s way out. Either inserting or pulling the ECM to or from its bay, there will be a hazard of touching the terminals of the battery with it.

If this has happened to you and your car is having problems with the engine, like needing to keep it accelerated to prevent the engine from shutting off, or if it is very hard to start the engine when cold, or if the engine is consuming much more gas than normal, then do not replace the ECM. Replacing the ECM will not fix the problem. Even when you touched the battery terminal with the ECM chassis and sparks came out, it was another part which got fried when that happened. It was the flowmeter. This part is also known as “air flowmeter” or “mass air flowmeter” (MAF). The ECM could have been fried because of the short circuit, but most of the times, I would say 99%, it is a problem of a fried flowmeter. To do a simple test, just disconnect the flowmeter connector and start your car. If the problems seem to disappear, then you will need to replace the flowmeter only. Below is a picture showing a couple of flowmeters used in the 1993-1995 BMW 325i and 525i. To disconnect the 4-wire terminal of the flowmeter, twist its cover counter-clockwise (like opening a water bottle) and pull it out.

The flowmeter is a device used for measuring how much air by mass is incoming into the engine. This information is needed by the ECM for doing the calculation of how much fuel to inject in different conditions, to keep a proper air/fuel ratio (AFR) balance.

The flowmeter is located in the air path way, between the air filter and the intake manifold and it has a round connector. If you stand in front of the engine, you will find it at your right side, beside the intake manifold. Check the picture below as reference.

Locating a replacement flowmeter at affordable prices can be done by searching eBay or a recycled/refurbished parts shop. A new flowmeter will be expensive and will do exactly the same job as a good, used one. Unlike many other automotive parts, a MAF type flowmeter that is in good working conditions, can be purchased with no worries as it does not have internal mechanical parts that wear out.

http://www.technicaldomain.net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

While we do not know the criteria used at the factory for installing it or not and in which vehicles, although we guess it is a location or a demographic reason, the good news is that it can be told if the immobilizer is enabled or not just by looking for the presence of a fuse, or better said, for the presence of a short pin, which resembles a fuse in size and shape, so we will call it a “fuse” from this point on.

There is a fuse box inside the vehicle cab and another one in the engine compartment under the hood. The one we will look for, is the one located in the engine compartment.

You will need to open up the hood of the engine compartment of your auto and standing in front of the engine, you will see the fusebox in the front, at the right, with a black plastic cover. Below is a picture of it (we are sorry for the dirt).

Lift the cover of the box by depressing the clips on the sides of it, and you will see something like the picture below (probably with less dirt).

Just look at the fuse that we circled in the picture below. If that fuse is present in your RAV4, then the immobilizer system is enabled in your auto, as that fuse is for powering the immobilizer system circuit. If otherwise, it is not there and you have been using your RAV4 like that (which means that the fuse was not intentionally taken out for giving you a hard time), then your auto has no immobilizer.

Again, this will apply to the 2001, 2002 or 2003 Toyota RAV4. We have not checked if it applies to other models.

By the way, it is a common problem, that if that fusebox gets damaged or burned by a short circuit and then replaced by a brand new one, it is the most common cause for the vehicle not starting. A brand new fusebox will always come with a fuse in that location and even a recycled fusebox may come with it too, so if your RAV4 does not use the immobilizer system and the fusebox has been replaced, the engine will not start until that fuse is removed. For example, in USA, we have hardly seen a 2001-2003 RAV4 with the immobilizer system enabled, while here in the Caribbean, most of them do have it enabled (yes I know what could be the meaning of this…).

If the vehicle is using or not the immobilizer system, is very important to know when buying either a brand new ECM, or a refurbished or used ECM, no matter if the part number matches or not. For example, you may need an 89661-42651, but we have seen that part number, both, with and without the immobilizer system and there was no distinction on the ECM that could identify the immobilizer status as being on of off.

I hope this helps,

Richard

Do you need to service your ECM? You will find the needed information and a professional service in the following link: Rav4Repair.com

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

To fulfill these requests, we will publish the basic immobilizer reset procedure by using external tools, not the included functions on each program, as many of them are undocumented or use custom hardware, not readily available for every user.

This procedure will also apply for the Toyota Virgin Dump collection, which is a group of files called dumps, as they were “dumped” out of the chip containing it, by using an EEPROM programmer to read such contents and not generated in any other way and also for the Toyota Corolla file and Toyota RAV4 File.

SOME BACKGROUND

The automotive immobilizer system use digital codes and transponder key data, all encrypted, to allow the system to recognize the vehicle owner’s ignition keys and disallow the engine to start with just any key. Data used for such process is stored in a memory chip, many times a serial EEPROM, located either internally or external to the engine ECU (Engine Control Module).

In most cases, the chip used as storage memory is an SMD (surface ounted device) serial EEPROM of one of the following families:

• 24C0x (ex: 24C02, 24C04, 24C08, etc.)
• 250xx (ex: 25020, 25040, 25080, etc.)
• 93Cxx (ex: 93C46, 93C56, 93C66, etc.)
• 950xx (ex: 95020, 95040, 95080, etc.)

All those above, are tiny 8-leads memory chips, measuring around 5mm x 4mm and the differences among them are memory size, communication algorithm, speed in KHz or MHz, voltage, temperature and some other minor factors. All you need to know about them is how to configure your programmer to read and write them. Nothing else, unless you are designing a system. For immobilizer reset you will only read and/or write the data inside them.

NOTE: There are some cases where the immobilizer data is not stored in a serial EEPROM, but in the main chip, which contains the engine control software. Such chip, may be a separate chip in the circuit board or may be part of the MCU (Micro Controller Unit) itself. Those cases are not covered here, only cases with serial EEPROM as storage, which are the most common.

PROGRAMMER

For the programmer (device programmer or EEPROM programmer), you may use any available, as long as it supports the serial EEPROM(s) you will be working with. There are many inexpensive equipment out there and it is fine to buy them, but if you are going to be doing this in a frequent basis, the best investment is to purchase a programmer that supports as many as possible EEPROM families, with capability of upgrading or updating it through software. Such can be obtained at EETools.com (USA Based) or MCUMall.com (Canada based). These are only examples, as I am not affiliated with any of them and do not know if they accept International orders either. I just recommend what I have had good experience with, which is EETools. Some customers have had good experience with MCUMall.

I have been asked about the Willem programmer. There are many versions of such programmer and it is quite economical. If you are going to invest on it, first make sure that it supports your devices, either by checking its compatible devices list or by contacting the manufacturers. I can not responsibly give my opinion here on Willem, as I have not had any personal experience with that brand, though either for good quality or for its prices, it seems to be prefered by many as it is mentioned in many forums that discuss the topic.

CONNECTION

The first obstacle that you might find will be how to connect or interface the immobilizer EEPROM to the programmer, so it can be read and/or written. The device (EEPROM) is an SMD (Surface Mount Device) chip, which means it has no leads (or at least too small leads to be inserted anywhere) and it is very small in overall size. At the right, you will see an example of an SMD SOIC chip, where Pin or Lead #1 is iedntified.

On the other hand, the programmer is a large device (pictured above) and it has a ZIF (Zero Insertion Force) socket, ready to accept the chip’s bigger cousin, the DIP or DIL (Dual In Package or Dual In Line) devices, which have 8 larger leads or pins (example pictured at right).

Since space is very important now a days, small versions of these EEPROMs are used, so for connecting them to the programmer, there are several ways, of which, we present the best two here. These are the best two ways because they both can be done without removing the EEPROM from its circuit, which would require unsoldering, with the many involved risks, like damaging the device by overheating it, static electricity discharge damage, braking it in the attempt of removing it, as many times they are glued in place before been soldered, and the less taken in care, loosing it. Yes! Loosing it! Several times I have removed the chip from the circuit, it has fallen to the floor and somehow seems like it found a breach to a wormhole… totally disapeared without I having the opportunity of at least reading it so it could be duplicated. That’s a horrible, but overlooked truth. If you stick to any of these methods, you will never loose a chip.

METHOD 1 – SMD SOIC-8 Clip

The first method is by using the famous SMD SOIC-8 clip. It is a clip, manufactured either by Pomona (picture at the left) or by 3M Company, which will press all 8 contacts at the same time against the chip’s small leads. It will have a terminal at the other side, where you may solder 8 wires to a DIL (Dual In Line) shaped terminal, so it can be inserted in your device programmer like if it was a normal DIL package chip.

Watch out for chinese replicas of the SMD SOIC-8 clip sold over eBay. Chinese replicas are not the same hardware, as it is manufactured with very bad quality materials and you will have a hardtime connecting it to the chip. Once connected, you will have problems reading it because of misalignment of the contacts. The plastic or polimer used is very weak and will not stand more than a couple of uses before braking or wearing out. If buying this from eBay or any other bidding or B2B market, make sure it is “Pomona” or “3M” brand.

You may get ribbons already assembled, with the clip in one end and the DIL terminal in the other, like the one sold in MCUMall HERE (also in the picture at the left), or you may buy the clip alone and construct the ribbon by your self. For it you will need the SMD clip, some parallel wire from an old hard disk or floppy drive data cable, two 4-pin headers and a small piece of perforated board (proto-board). Just make sure to connect pins 1 through 8 of the terminal, in the right order, aligned with pins 1 through 8 of the clip. The illustrations below are example to give an idea.

You will need to splice the ribbon. It ususally has 40 wires in parallel or so. First cut both whatever terminals that are installed on both ends if any, of the floppy or hard drive ribbon you are using as the source of your wire harness.

Count 8 wires from either edge and do a small cut in the separator between wires (A). Pull away the now 8-wires ribbon (B) and in the same way you separated the 8 wires from the main ribbon, separate each one of the 8 wires (C) to a small length at one of the ends (D). Now do the same in the other end of the 8-wire ribbon, but this time, pull a little bit longer the separated wires (E). That longer wires will be spliced and soldered in the clip’s terminal.

First, make sure that you configure the wires in the sequence described below. That way, the ribbon cable can be used in a linear way and will not need to be folded in any way. Mark wire #1 in red or any other color so it can be distinguished, as you will need to know it when reading and/or writing to EEPROMs.

The other end of the wire will need to be spliced too and soldered in the DIL-8 terminal, matching wire number with Pin number. Use an ohmmeter or continuity tester to make sure that (1) the wire numbers match with pin numbers and (2) that there is no continuity between every contiguous pin. Otherwise, it means that a short circuit is present.

Below is a picture of a typical homemade SMD SOIC-8 clip and how it is engaged over the target SMD chip to be read and/or written.

I am just giving this information in case you wish to do it yourself, but after seeing all the hassle of making your own SMD clip ribbon, you might consider buying an already made one. They are not expensive, already error free and ready to be used.

METHOD 2 – Micro Pincers “Spider”

The other method is by using micro pincers. Again, the same advice about replicas. I have tried some made by Pomona and some chinese replicas. I had a hardtime with replicas. Pomona’s brand was very good, but the ones that performed best were the HP brand ones. Yes, Hewlett Packard. Good micro pincers may be obtained at Digi-Key Corporation.

With the micro pincers, you will be doing the same as with the SMD clip, but in this case, you will need to connect the 8 pins one by one. In no time you will master the technique and believe me, it is way more reliable than the clip or any other method, as the pincers are designed to grab each one of the diminute leads of the chip, without shorting them and once it is locked, it will read and write flawlessly.

NOTE: Please do not confuse micro pincers with micro grabbers. They are not the same. Micro grabbers are not intended for SMD devices. The micro pincers are “Y” shaped when opened and the micro grabbers are “J” shaped when opened. We need the ones with the “Y” shape. An example is at the right.

This is my favorite method of accessing SOIC-8 chips. It is in-circuit and very reliable at the same time. When using the previoulsy described method with the SMD clip, I have had a good experience, but sometimes you will need to play with it a little bit and accomodate it more than once, as every EEPROM package is slighly different and some will not allow the clip to grab them reliably enough. The lower the profile of the device to be accesed, the more difficult it might be. In some other cases, the leads of the chip will have materials that might prevent from good electrical contact, such as cases where any anti-corrosion treatment has been applied to the circuit board, like the most common one which is silicon based.

For constructing the same ribbon using micro pincers instead of the SOIC-8 clip, the process with the ribbon will be the same, with the exception that instead of the SOIC-8 clip terminal, you will connect that end of the ribbon to 8 micro pincers. It is very important that you number every pincer accordingly. Otherwise you will be lost at the moment of connecting them to an EEPROM for programming. Below is an example of a typical homemade micro pincers setup with a ribbon.

The diference in performance between the SMD clip and the micro pincers, relies basically in two things. One is that the clip will make contact to the front face of the device leads. While it will allow to make good contact in normal cases because it will find a larger contact area, such area will likely be coated with any anti-corrosion material as it is more exposed than the side areas. The second thing is that the clip excerts all its pressure at the same time to all the leads, making it strong in a few leads and weak in the others if not well balanced.

The micro pincers, on the other hand, will connect from the sides of the leads, which is less electrical connection area to grab, but will do with larger force per lead than its counter part, needing not to be balanced. Below is an example of a micro pincers “spider” connected to an EEPROM to be programmed.

DATA MANAGEMENT

So you might be asking by now, what will I read or write to the EEPROM once I successfuly connect it with either method? Well, you will need to write the specific virgin file of that model, if it is readily available, or will need to use any of the softwares intended to “virginize” the files first and then write the “viginized” file.

Let’s explain it in more details, but before doing that, first I would like to make 5 very important points here. The first one is that while you are working with EEPROMs in-circuit, it means that you will access the device with the hardware you have (clip or pincers, plus device programmer), but it also means that you will access part of the rest of the ECU circuit because the device is still soldered in the circuit. Right now there are no concerns of damaging the circuit, as the signals used by programming devices are safe, provided that you connect your clip or grabbers the right way. If you do a wrong connection, it is not very probable, but changes might occur in the circuit next to the target EEPROM, which includes its neightbor, the MCU or micro controller unit, so please make sure that the target device is hooked or interfaced the correct way, which means lead 1 of the clip with lead 1 of the chip, etc. That is other way of saying, ground with ground, +5v with +5v, etc.

The second point I want to stand out here is that when you are programming in-circuit, you are transfering data from your PC, through your programmer to the target device, which is a serial EEPROM in this case. Such data can be corrupted before it reaches its target. The main reason for this is the crystal oscillator. It is an electronic component used to provide the clock signal to the MCU just like a pacemaker does to the heart. This part is made of quartz, as its name says, but it is encased in a protective metal package. Without power, the MCU is completely off as we need it to be at the time of doing the programming, but in some cases, power from the programmer will go throgh our interface to the chip to be programmed, but will also go to the rest of the circuit. If that power reaches the MCU, it will attempt to start working and communicate with the target EEPROM, corrupting the data we are sending. We can cut power to the MCU, but will be a risky and tedious job and will make the whole process troublesome. The good thing is that we will achieve the same by keeping the pacemaker off. It is done as easily as running a wire, shorting the quartz crystal’s leads. Just locate the crystal, which is always near the MCU, and short (bridge) it. If the ECU has two MCUs like in many modern ECUs, then short only the crystal which is near the MCU connected to the EEPROM to be programmed. Both, the crystal and the MCU, will be near the target EEPROM. An example is shown below, where a 2-MCUs ECU is being programmed. The crystal that was bridged was the one near the MCU connected to the target EEPROM.

The third point is connection reliability. Before reading, writing, burning, zapping or whatever you wish to do to the EEPROM, once connected, you will first need to make sure that connection is ok. You will do that by selecting the EEPROM type in your programmer. If it is a NM93C56AN, then simply select “93C56″ for example. If your programmer allows you to be more specific, like brand, prefixes and sufixes, then be more specific. Then, do a quick confirmation read by clicking on “read”. Once read, notice the 4-digits checksum (32-Bits) and read the EEPROM again two more times while looking at the checksum. If the checksum stays the same all three times, then it is well conected and ready to program. If checksum fluctuates, then something is wrong. It may be caused either by a loose connection of the clip or pincers, by a crystal not been bridged or bridged the wrong crystal or simply by selecting the wrong device from the programmer’s list. If checksum read “9AE2″ for example, it must be “9AE2″ all three times. Until it is not happening, the setup will not be ready to either read or write to and from the chip.

The fourth point is be always concient where pin #1 goes. If you are to remove or replace a chip, note where pin #1 goes. The same when reading and programming EEPROMs. Pin #1 will tell you where the count starts and will be the reference point on how to put the clip or locate each one of the micro pincers. Get used to always note where pin or lead #1 is heading to.

The fifth and last point is ALWAYS BACKUP FIRST! It does not matter what kind of work you will be doing with the EEPROM, always save backup copy of the file inside it first. If for any reason, you need to put it back as it was the first time, you will not be able to do it without a backup! With time, we learn how to recognize certain parts of the file inside the EEPROM, like keys, VIN numbers, Odometer settings, whatever. Sometimes we will need that data back for any reason, for an emergency, for simple comparing with other files, etc. A backup copy will save your beloved A$$.

The process to “virginize” or reset the immobilizer is as mentioned earlier, as simple as writing the right file in the immobilizer EEPROM. So if you already have the needed virgin file, the steps are as follows:

• 1. Locate the immobilizer EEPROM, either in the ECU or in a separate Immobox. For knowing this, you will need to look for reference in a database either on software or online. There is no rule or standard for this. Every manufacturer use their own standards.
• 2. Set your programmer by choosing the EEPROM type and the virgin file to be loaded in memory. Some systems will only allow to reset the immobilizer and some will allow to totally eliminate it. When eliminated, you can cut any standard key and that will be enough to start the car. If reset, you will need a programmed key which is compatible with the vehicle’s system so it get automatically registerd by the just reset immobilizer, allowing it to start the car.
• 3. Bridge the crystal of the ECU or Immobox
• 4. Connect your interfacing hardware to the target EEPROM and do the read test to check for good connection.
• 5. If connection is ok, load in memory the needed virgin file from your hard disk and write it to the immobilizer’s EEPROM.
• 6. Do a new read test, but this time to check if the file was written correctly. The checksum should be the same as when loading the file from disk. If it changes, it is possible that EEPROM was selected wrong from the programmer’s list, the EEPROM is write protected (only newer EEPROMs) or the EEPROM is damaged. There is no possibility of a bad connection here if the read first test was passed. Also, if the checksum is different from the checksum when loading the file, but it reads three times the same now, it is not a connection problem. Data simply was not stored right because any other reason.
• 7. If read test is ok and checksum matches, then the ECU or immobox will be ready to be reinstalled in the car.

If you do not have the virgin EEPROM ready, but have a software like immo killer, immo tool, immo cleaner (otocheck), etc, then you will need to look in the list of the software and see if the application (vehicle) you are working with is present. If it is present, then you will need to do the above procedure, but in step number 5, the procedure would be:

• 4. …See above…
• 5A. If connection is ok, then run the immobilizer virginizing software you have.
• 5B. Select the application from the software list. If you are working with a 1998 Toyota Camry for example, select so from the list if available.
• 5C. Read the file from the ECU or immobox with your prigrammer and save it in a file with the extension “.bin”. For example 98Camry-no-virgin.bin
• 5D. Load the just saved file with the virginizing software and select “Fix” or “Clean” or whatever button they have to start virginizing the file.
• 5E. After one or two seconds, the file will be virginized in the memory of the software. Save a copy in your hard disk, again with the “.bin” extension. For example: 98Camry-virgin.bin
• 5F. Load the just virginized file from your hard disk to the programmer’s memory and write it to the immobilizer EEPROM.
• 6. …See above…

SOFTWARE

There are several softwares out there intended mainly for virginizing the immobilizer system. Many have lots of files or fixes in common. There are other files or fixes that will be unique to that software. For example, Immo Cleaner v2 (OtoCheck) will have the same Toyota files that Immo Killer v1.0 does, but in its Toyota list, Otocheck will cover a few more models. As another example, ImmoKiller will be very similar to ImmoTool, but Immotool has a Toyota key generation tool that Immokiller lacks. The best would be to have a copy of each one I guess, though it would be somewhat expensive.

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

For some time, we were wondering about the cause of an intermittent power loss on the car of one of our customers, that seemed to have no cure, as all the engine parts and electronics we checked tested ok.

As we made the tests, the problem was tracked down to possible problems with the ignition system, specifically suspecting of too low ignition timing advance. We went to that conclusion, as the reading with a scanner was a sudden drop in degrees, of ignition timing advance, to a lower than usual level when the problem started showing.

Logically, we first checked the spark plugs, ignition wiring and ignition parts for damage and since those parts tested good too, we took out the ecu (engine computer) for inspection, almost sure that the problem was there. To our surprise, the ecu was good too. Running out of ideas for the possible cause of the problem, we observed one more time the collected facts and looked like the problem appeared only right before a drop in the reading of the ignition timing. Of course, lowering the ignition advance by several degrees will cause a loss in engine power. In this case more than a loss in power, it made the car to stall when the problem showed.

Now, with the facts we collected and confirming that it was a drop in ignition timing, we started looking in our diagrams in search of electrical components that could be associated with the sudden drop in ignition timing under normal circumstances. I say normal circumstances because until now, we couldn’t find any damaged or faulty part.

By consulting the diagrams, we found the only thing that might be causing that drop in ignition timing. We saw a knock sensor wired to the ecu. We were not aware that the Korean model we were working on had any knock sensor in its system’s circuitry. We immediately replaced the sensor convinced that we finally hit the problem. We were shocked to see that the problem came back after a few minutes of driving the car. The worst thing about such problem was that it was an intermittent failure and we were not able to duplicate it all the time, making it more difficult to troubleshoot.

Luckily, it occurred to us that if the knock sensor does its work by detecting “knocks” or detonations, then either, detonations might be occurring unnoticed, producing the drop in timing, or something similar to detonations was occurring. We found out that the sensor was really doing its work, but it was not sensing any detonations, but a very similar sound coming from a loose metallic part near the exhaust manifold. Any time that the loose part vibrated in a certain frequency, the knock sensor detected it and the ecu dropped the timing to protect the engine in case that detonations occurred. It all was part of the many program routines integrated in the engine computer for protection of the engine. Detonations might brake the engine and once they occur, can be prevented or at least lessen by lowering ignition timing advance, and so did the “confused” ecu. After several seconds that knocking or detonations cease, the ecu will move back the ignition timing to where it was and will continue doing corrections.

The knock sensor really is a piezoelectric microphone, “hearing” at the engine all the time. A piezoelectric element is used due to its capacity to pickup higher frequencies, around the frequency of the signal that an engine knock produces when a detonation occurs, also known as “pinging”. The signal it generates by “hearing” the engine, is then processed by the ecu. A complex process is done by a microcontroller in the ecu in the “knock sensor amplifier” circuit, to filter out the “heard” signals. This process will discard regular occurring noise and take action on real knocks or detonations. Even when the filtering process is complex enough, the vibrations of this metallic shield were either, not filtered out because of a glitch in the filter circuit design, or the generated noise was simply too similar to engine knock, fooling the filtering circuit.

Below are two examples of knock sensors. A knock sensor, being a piezoelectric part, when tested with an ohmmeter, it should measure infinite resistance or a very high value, from 500,000 Ohms to several MegOhms (1×10^6 Ohms).

Engine knock is very specific in every car or application and it will not “sound” equal in all models. For us, all engine knocking will sound the same, but for a sensitive, high speed computerized circuit, it will have different sound in different models, which offer different environment. That is why, every ecu computer has a different arrangement or programming for the model it was made for. Some car manufactures, use a generic ecu for several car models that are similar, but they put a different programming on each one, suitable for that application. GM for example, used to put similar ecus in different models of the same line, but each one had a different programming and besides that, each one used to have its own detachable knock filter circuit, so it could be transported to a new ecu should the ecu needed replacement.

Well, I think that the bottom line is to keep all mechanical parts tighten, in place and clean, as the minimal thing may negatively affect the engine of your car, due to the complex computerized systems installed on them now a days. Something that looks inoffensive, may cause lots of untraceable and annoying troubles in our vehicle. I hope this experience helps for correcting the same or similar problems on other automotive cases not solved yet.

© TechnicalDomain

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

When you replace your 2001, 2002 or 2003 Toyota RAV4 ECM (car computer or engine computer) with an used unit, either bought at eBay or at a salvage yard, junker, etc., if your vehicle is equipped with an immobilizer system, which is an anti-theft security system, you must either reprogram the ecm to work with your existing keys, or buy new keys, which must be cut and programmed for matching the ECM unit you just purchased.

In this article, we will cover the part where the ECM is reprogrammed, as that is the easier way, and will use as an example the 89661-42820 RAV4 ECM. That part number is to mention just one, as this procedure will cover all 2001 – 2003 models, either 4×2 or 4×4 wheel drive.

For reprogramming, if you have an EEPROM programmer, you can do the programming either in circuit or off circuit by using a reset file for the immobilizer EEPROM in the ECM circuit. If you have such a programmer, you may get the immobilizer reset file for download at:

2001-2003 Toyota Immobilizer Reset file Download

You may check the following article if you which to do the programming “in-circuit”:

Reading and Writing Immobilizer EEPROMs in circuit.

Otherwise, you will need to remove the EEPROM, reprogram it and resolder it back in the circuit.

If you DO NOT have an EEPROM programmer, but have some soldering skills on electronic circuits, then keep on reading, as the following procedure will help you do the job without investing in a programmer.

You will first need to get a “Immobilizer Reset EEPROM“. What to do with that or what is it for? Well, first of all, an Immobilizer Reset EEPROM is an EEPROM (in this case a 25080 SPI EEPROM) already programmed with an immobilizer reset software, which after installed in the ECM circuit, it will put the ECM in auto-register mode. that means that after installing the ECM back in the vehicle, it will register the first key you use on it. Of course, that first key will be your existing key. After that, the other keys you have will also work. For the “what to do with that” question, you will just replace the EEPROM that is in the circuit of the ECM you bought, with this reset EEPROM. Your replacement ECM will be in auto-register mode, as explained above. In that mode, you just put your existing key in the key lock cylinder, wait for 10 seconds and it is ready to use. The ECM will be locked to your keys and will ONLY work with them, the same as buying a brand new ECM.

For this job, you will need to unsolder the existing EEPROM inside the ECM and solder the reset EEPROM in its place. The existing EEPROM will have the markings “25080” on it and it is located near one of the micro controllers (big black squares), with the reference “IC1003” on the circuit board. Below is a picture of the ECM’s circuit and some details for easily locating the parts.

In the picture above, you can see the location of the immobilizer EEPROM. Take note of the orientation of Pin#1, as the reset EEPROM must be installed the same way. For replacing the EEPROM, just unsolder the existing one and solder the reset EEPROM in. You may be thinking at this time; “But wait! That it is an SMD (Surface Mounted Device) chip! and my soldering skills are limited to “through hole” parts. Well, it is an SMD chip, but it is very easy job if you are able to do regular soldering on circuit boards. Check the pictures below on how to do it.

That’s it! After soldering all the 8 pins of the EEPROM chip, make sure that; again, pin #1 is pointing to the right direction, make sure that there is no soldering debris on any part of the circuit and make sure that you put the new (Reset) EEPROM and did not install back the same EEPROM you just took out without noticing

Now is time to put your ECM back together and reinstall it in your RAV4. Put your key in the cylinder lock without turning it to any direction, wait 10 seconds and then start the engine. If everything was done right, it will start and run as normal.

© TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Sometimes when working with immobilizer EEPROMs, the ideal way of programming the EEPROM is by doing it while it is in the circuit, as removing it, programming and resoldering it back to the circuit, adds a bit more of effort to complete the job.

Doing it “in-circuit” can be accomplished by using the SOIC-8 clip, connecting it over the EEPROM chip while it is in circuit, but sometimes, some inconveniences are present. Some of those inconveniences are; the need of cleaning the EEPROM leads from any protecting coating the ECM might have, or the fact that the EEPROM in question might have a too low profile, making it impossible to keep the clip in place, or the situation that we will cover here; the ECM circuit is too sensitive to the voltage that the EEPROM programmer injects to it, for working (reading/writing) with the EEPROM. In this case, the problem is that the micro controller of the ECM is attempting to start (run) with the reading supplied voltage. Of course, thus will vary from ECM to ECM and from programmer to programmer.

The solution for this situation is to disable the crystal oscillator of the micro controller (MCU) that is attempting to run with the programmer’s voltage. That is accomplished by simply jumping the crystal by running either a 0.1uf capacitor or a small jumper wire across it. In the picture below, it is shown how a 0.1uf capacitor was temporarily soldered across the crystal terminals to disable it.

In the event that you don’t have the SOIC clip to read and write the immobilizer EEPROM or simply you don’t like it, below is pictured another approach for doing it. For this, you will need to construct the harness, composed of 8 micro clips and a 4-pin dual header for connecting it to the programmer. Once constructed, you will be able to use it over and over. It will have even more life span than the SOIC clip itself.

There are some Internet stores that sell some of the equipment used on the described jobs. For example, you may get the SOIC-8 SMD clip complete with its harness and ready to use from MCMall. For the link, just click on the picture below:

The microclips can be obtained from the electronics distributors, DigiKey. The link is below along with the picture.

Good luck and be always careful when working with sensitive electronic circuits by using ESD (ElectroStatic Discharge) protection to avoid damaging the circuits.

© TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

If you own a 2001, 2002 or 2003 Toyota RAV4 vehicle and you are having problems with the automatic transmission, which symptoms are harsh shifting, loss of power, launching on second or third gear and/or hard engagement when it is put in reverse, then you should know that those problems are caused by a defective engine computer, which also controls the automatic transmission.

These problems are erratic and may only show at intermittent intervals or when the vehicle is warm or have been driven for a specific time. Sometimes it happens one day and the next morning it does not show.

When the computer (ecm or ecu) is defective, it will be presenting the problems mentioned above and many of those vehicles will also show the trouble codes P0750, P0753, P0755, P0758 and/or P1760.

The defective ecm computer, stops to correctly control the transmission shifting solenoids, activating and deactivating them erratically. This must be repaired before the transmission suffer any of the common damages caused by this problem. Reprogramming or updating the computer software will NOT fix the problem. It must be REPAIRED.

If your RAV4 is presenting loss in power when launching, that is, if you stop in a red light for example and when continuing, your RAV4 moves like it is carrying a very heavy load, that is because the vehicle is staring at second or third gear instead of first gear. That, in no time, will burn the transmission clutches. Please, be aware that if the computer is not repaired and you continue using your RAV4 like this, a transmission repair bill will add to the overall cost at the end.

If the vehicle is out of warranty, most owners will do the logical thing to do, which is going to a transmission repair shop. If your transmission have not sustained any damage yet, a transmission repair attempt will not fix the problem.

Toyota issued a bulletin where it is recommending that the ecm computer be replaced by a new one, but since this have affected so many vehicles (more than 240,000 units), Toyota extended their warranty to cover this problem specifically. The new warranty covers up to 10 years or 150,000 miles, whichever comes first. This new warranty will cover both the ecm computer and the transmission. If you are having this problem and your RAV4 is less than 150,000 miles, you should first visit your local dealer before bringing your RAV4 to be repaired to any independent repair shop. The documents about this bulletin and warranty extension may be downloaded in the links below:

REPAIRS

When the computer is send to be repaired, it should be checked, repaired and TESTED. We are highlighting on “testing” the computer, because there are several individuals, offering the repair service and while that is ok, many of them are NOT testing the computer after the “repair” is performed.

We were approached by someone that ordered the service from someone on ebay from Ohio, and after he received back his ecm, his RAV4 still had the same problems. He told us in his own words;

Needless to say about the frustration that this customer had about this. This guy was offering his “service” for a very low price, but looks like the quality of his job is as cheap as his price. We checked the computer and he damaged the computer beyond any possible repair. Whatever “job” he did was very poor and soldering was like if he was a novice. We had to replace the computer at last and his transmission problems went away immediately. Other guys from Florida are selling some “remanufactured” computers and when we checked some of them, they were all covered with a black epoxy that made the ecm to be disposable, as it would have to be thrown away in the event that the circuit area beneath that epoxy fails. Very bad practice in our opinion.

So, about testing the computer, as you may already know, most of these vehicles came with a security system called immobilizer. This system will not allow you to run your RAV4 vehicle with other than your keys, which have a security chip integrated in the black plastic handle of each key. A code for running your vehicle is programmed inside that chip on the key, as well as in the ecm computer. Both codes must match after a security algorithm is automatically run by the system as soon as you insert any of your keys in the keylock cylinder.

To actually test your ecm computer after been repaired, it must be installed in a test vehicle. In order to run the engine for the tests on the test vehicle, the ecm under test must be prepared with the test vehicle codes. Otherwise it will not run. If it does not run, no test can be done. As simple as that.

Not to mention that if the ecm is successfully programmed to do the test, it must be programmed back to the codes it had before. Otherwise, the ecm will be repaired and tested, but will not run on the owner’s RAV4, because now it has a different immobilizer code.

For a quick and quality repair, where the ecm is checked, repaired and tested you may visit the following website:

After your ecm is checked and repaired, it will be prepared with the test vehicle immobilizer code and returned to your vehicle’s code after the test is done. It is achieved by removing the owner’s immobilizer eeprom chip from the ecu circuit and installing ours for testing. After the test is done, the original eeprom is reinstalled. This means, no programming will be needed as soon as you receive your repaired ecm computer. Just plug it and you are ready to drive it.

Your ecm will be in good hands and in no time you will drive a NEW RAV4. For more information, you may visit the website above or send an email to info@otherdeal.com

OTHER RELATED INFORMATION

Pinout of the 2001-2003 Toyota RAV4 ECM is depicted below:

Location in the vehicle of the ecm can be seen in the next picture:

Here is a partial schematic of wiring of the solenoids on the RAV4 automatic transmission from the ecm. Note that they are all a total of 10 wires, driving 6 solenoids, 4 of them with two terminals on each one and the other two with only one terminal on each one, with the other terminal of those two coils wired directly to chassis ground.

And here is the terminal connector for those ten wires. This connector is wired to the solenoids assembly. You will see in the picture below the perspectives of each harness connector. Also, the terminals for the SL1, SL2 and S4 solenoids are shown, so electrical resistance tests can be done on their coils. The solenoids resistance in ohms is also shown in the illustration, which are the same for SL1 and SL2, 5.0 – 5.6 ohms and 11 to 15 ohms for S4. Any value out of that range means a defective solenoid. If resistance is ok, then you should proceed to test the solenoids in action by disconnecting the 10 wire terminal and applying voltage from the battery, through a 25watt bulb to the solenoids directly. If a clicking sound is not heard when energized, that is indicative of a defective solenoid too.

Below is the position of the solenoids in the assembly in front of the automatic transmission.

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Quick and easy solution for curing the annoying hesitation, jittering, lag back feeling, stalling or whatever you wish to call it, which happens when you are accelerating your car.

(Note: While this article is dedicated to the Toyota Corolla late models, this will apply to most cars equipped with a MAF or flow meter sensor, either from Toyota or any other brand, like Nissan, Mitsubishi, etc.)

If you own a 2004, 2005, 2006 or 2007 Toyota Corolla and your car hesitates when you accelerate or it hesitates when driving, you should try the solution described here. Below is a list of the behavior your car may show that tells that you should try this procedure before going to a mechanic or repair shop.

• The accelerator is slightly pressed while the car is running and it slightly jitters or hesitates
• After completely stopping the car (a red light for example), it hesitates when you accelerate to continue driving
• Engine power is below the usual level
• Sometimes check engine light turns on

You should know that while those problems can be caused by several issues, including low quality or altered fuel or even a loosely tighten fuel cap, the most common cause is a dirty MAF flow meter sensor.

The MAF sensor (Mass Air Flow Meter Sensor) is in charge of detecting how much air (in mass, not volume) is coming in to the engine, so the ecm computer can calculate the amount of fuel to be injected.

Some times this sensor gets contaminated by lots of microscopic debris that scape the air filter and accumulate on its sensing parts over time. The resulting effect is that the MAF flow meter sensor gets less “sensible” and detects less air than it is currently entering the engine. The reaction of the ecm computer will be to inject less fuel to keep the air fuel balance, taking as reference the false reading of the MAF flow meter sensor. This will produce a too-lean mixture, which is responsible of the hesitation, the loss in power and the check engine light.

If your car engine, besides the hesitation, is also producing knocking or engine pinging at high loads, like when going up through a hill, it is attributed to this too-lean condition.

Before going to an auto parts store or to a mechanic to fix the problem, you should try fixing it your self. If the problem is a dirty MAF flow meter sensor, the solution is to clean it, plain and simple. That may save you some money that a mechanic will charge for cleaning it (you could do the same) or for replacing the part when most of the times it is not damaged, just dirty or contaminated.

Here are some guidelines to do it by your self. If you do, you will be glad that you saved money and learned how to do it for the next time it happens to you, your family or friends.

First of all, you will only need a #2 Phillips screwdriver (shown in the picture below) for removing just two screws and a spray can of electrical cleaner, specially designed for these jobs. Though I said “specially designed”, don’t worry as it is available on any Auto Zone or similar stores. The brand “CRC” is an excellent one and it is also shown in the picture below (I am not affiliated with CRC or Auto Zone in any way, just sharing my experience).

Now, you will need to locate the MAF flow meter sensor in your Corolla. It is very accessible and no mechanical experience is needed to do this. In the picture below, the location of the MAF flow meter sensor of the 2004, 2005, 2006 and 2007 Corolla (1ZZ-FE Engine) is shown. You will find it by opening the hood of your car’s engine compartment and looking at the air intake assembly behind the vehicle’s battery. It is attached in place by just two small Phillips screws. Take the screws out with a #2 Phillips screwdriver, carefully not to drop them off. If they drop, you may end up loosing them and while they can be easily replaced, this will turn from a quick fix to a time wasting ‘searching for a similar screws’ job that might involve a trip to the hardware store.

After removing the two screws and putting them in a safe place, now pull out the MAF flow meter sensor. Sometimes it could feel a little bit attached, but if both screws are removed, it will come out.

In the next picture, it is shown the MAF flow meter sensor already pulled out. Now you must disconnect the wiring harness that is attached to it, by pushing a plastic clip located in the plug, while pulling away the plug at the same time. It will easily come out.

With the MAF flow meter sensor already unmounted from your car’s engine, put it in a table over a paper towel or a cloth and with the CRC cleaner, spray directly to the connector harness to clean the contacts from debris and dust. Just spray it with full force for a couple of seconds. You should wear eye protection or be very careful so the spray back does not get in your eyes. Also, since this product is highly flammable, do this away from open flames, heat sources and in a ventilated area.

Now what will really fix the engine hesitation issue; spray with full force inside the MAF flow meter sensor openings for a couple of seconds on each opening. Avoid the straw of the spray can, to get inside the MAF sensor and touch anything inside. After that, repeat one more time and put the MAF sensor upside down, so the excess liquid drips out. Allow enough time for the MAF sensor to be completely dry before reinstalling it in your vehicle. The CRC chemical is designed to dry almost instantly and it does, but spraying for a few seconds over the MAF sensor’s surface, will considerably lower the temperature, causing condensation from the environment moisture. Just allow it to dry completely before putting it back in the engine. A good trick is, if the engine is warm by chance (you drove the car before doing this job), just put the MAF sensor on top of the plastic cover of the engine for at least 15 minutes and it will dry completely.

IMPORTANT! One final note. Please only use the chemical (spray) described here or one that is for similar purposes and (1) will not harm polymers (plastics), (2) will not harm electrical connections (not acidic) and (3) most important, will not leave any residue when it vaporizes. Cleaners that contain lubricants, like WD-40 for example, may not be used for this job. Any residue left inside the MAF sensor will damage the part. This job is about removing contaminants, not replacing them with some other substance.

That’s it! Enjoy your new-again Corolla!

Thanks for reading!

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Installing a performance chip on 1992-1995 Honda JDM computers uses the same method as described on other posts on this website. You may use the search function above for those other publications. What differentiate the installation on JDM ecus from USDM, Canadian, European, Australian and some others, is the need of installing Surface-Mount-Devices (SMD’s). The same installation kit of the P28 and other OBD-I Civic / Integra ecus is needed, but the parts are smaller. These parts are; the 74HC373 chip, the “J1″ jumper and the two bypass capacitors, which instead of being a through-hole mounting devices, these are soldered on the surface of the circuit board. They are smaller and a little bit more difficult than their counter parts, but still, it is a simple job. The resistor “R54″ is not needed on this installation and the two capacitors are optional, so the jumper and 74HC373 latch chip will be depicted only.

Here is a picture of the 74HC373 SMD Chip

Note: This job requires average skills on electronics soldering, but it doesn’t require skills on electronics. You may always bring the computer and the new chip to any TV or electronics shop so they can install the chip and the other parts, then you just install back the computer in your car. Also, all connections should be verified before and after soldering the socket. Take care not to jump connections with soldering or brake circuit traces by over heating. Notice that there are connections above, bellow and inside the circuit board that are sensitive to too much heat. Always clean the finished job with a mild solvent like alcohol

This installation is needed only once. After that, it will be a matter of pulling out one chip and inserting any other if you would like to switch between different tunings or for comparisons. Whenever you wish to go back to stock mode, please do not uninstall anything. Just cut or remove jumper “J1″. Installing back that jumper will switch to performance mode again, as long as the chip is inserted.

Your computer is located at the passenger’s side kick panel or lower dash. After locating the computer in your vehicle, remove the bolts that attach the computer to its place and carefully disconnect the harnesses that are plugged to its back. The harnesses can be disconnected by pushing a clip, located on top of the plastic connectors and pulling it back carefully. After uninstalling the ecu, put it in a flat table and remove the bolts securing both top and bottom covers using a #2 Phillips screwdriver. Remove the bolts that fixes the small board on the top of the main board and CAREFULLY flip it back, taking care not brake the flexible cable ribbon attached to it.

(Click on image to enlarge)

For installing the chip, you will need to locate the footprints on the circuit board where the parts to be installed belong (See picture above). In regular cases, there will be no parts installed in the targeted spots, just the footprints. You will only need to clean the spots (remove the solder) and then solder in place the corresponding parts. First, solder in place the 28-Pin socket and the 74HC373 small chip (SMD – Surface Mount Device).

After that, flip over the ecu and locate the spot of the “J1″ jumper on that side of the circuit board. Just jump it with a small piece of wire or with a zero-ohm surface-mount resistor. The best is a low height arc shaped jumper made with a piece of wire, so it can be cut / joined for switching between stock and performance modes. If you decide to put a switch on the ecu wall or cover, it is ok, but keep wires short. Check picture below for location of “J1″.

Now, insert the performance chip on the 28-Pin socket. Please use the drawings above and below as reference, to make sure you are installing the chips the right way in the socket, since they will fit both ways, but will only work in the right one.

Now you are ready to put back together your ecu and reinstall it in your NEW car !!!

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Installing a performance chip on 1988 -1991 Honda Civic / CRX is a single procedure that consists of removing the stock chip, soldering a socket in place and inserting the performance chip on the socket. This instructions are similar to the instructions for installing a performance chip on OBD-I Accord and Prelude elsewhere on this website.

Different from the OBD-I Civic and Integra ecus, which you must add some extra parts, the OBD-0 Civic and CRX ecus do have a stock chip that can be replaced, making it simpler in a way, but tougher at the same time in another, because you will need to unsolder the stock chip, which is held with soldering in both top and bottom sides of the circuit board.

Note: This job requires average skills on electronics soldering, but it doesn’t require skills on electronics. You may always bring the computer, the new chip to any TV or electronics shop so they can install the chip, then you just install back the computer in your car. Also, all connections should be verified before and after soldering the socket. Take care not to jump connections with soldering or brake circuit traces by over heating. Notice that there are connections above, bellow and inside the circuit (multi-layered) board that are sensitive to too much heat. Always clean the finished job with a mild solvent like 91% – 99% isopropyl alcohol.

Your car’s ecu is located at the passenger’s side kick panel or lower dash. After locating the computer in your vehicle, remove the bolts that attach the computer to its place and carefully disconnect the harnesses that are plugged to its back. The harnesses can be disconnected by pushing a clip, located on top of the plastic connectors and pulling it back carefully.

This installation is needed only once. After that, it will be a matter of pulling out one chip and inserting any other, every time you want to switch between “Stock” and “Power” modes. These instructions cover all 1988 to 1991 (OBD-0) Honda computers that are listed at the top of this page for Civic and CRX.

For installing the chip, just find the 28 pin chip marked as “M38256AP-xx” (see the picture bellow). It must be unsoldered and replaced with the 28-pin chip socket, and then the new performance chip must be inserted on it. Make sure that you align the chip so pin #1 goes to the same place of the old chip (lower left corner of the chip in the picture bellow). No other parts are needed on these models. After inserting the chip, just put the ecu back together and reinstall it in your car.

Note: The “xx” after the “M38256AP” is different in every computer. That is the code of the program written in the chip. The picture below is an example of the PM6-A09 (65). For PW0 it will be “71“, for the OBD-0 PR3, there are two versions, “58″ and “93″, so you must first open and check your ecu before buying a performance chip, to make sure it will fit. Every ecu has its own code.

One good technique of removing the chip, though still requires patience, is soldering all the pins of the stock chip together and fill it up with molten solder, then heating both sides at the same time and gently prying it with a flat screwdriver. This, of course, will require two good soldering irons of 35 watts. Please do NOT use soldering irons hotter than that or it may damage the ecu and the stock chip. The best non expensive and very good quality for this are the Weller brand. Radio Shack’s irons are NOT appropriate for this. Those are more for hobbyists than for heavy jobs like this. Before starting, always spread in all the area to be worked some electronics soldering flux paste to facilitate the job, as it cleans contacts and rejuvenate soldering when heated.

After you finally and GENTLY pull out the chip, you must clean it with desoldering braid so it can be used again whenever you want to go back to stock mode. Otherwise, if you damage the chip when removing it, you will need a copy of the stock chip if you want to go back to stock mode. You can either burn your own or order it from places like http://www.otherdeal.com Just drop a quick message at the contact form on that page requiring what you need. Also, on that page you can pay for the service of installing the socket for you, handing your ecu over the mail.

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

This should be reverted if a performance chip is used, since the chip advance timing in various points by itself already and adding any extra manual advance will possibly result in dangerous detonations, also known as engine pinging or pre-ignition. This, could be very destructive for the engine at high speeds.

Here are some tables showing the stock setting of some Honda cars that are chipped often.

92-95 Civic EX (P28 Chip, D16Z6 1.6 L SOHC VTEC Engine) and
92-95 Civic DX (P06 Chip, D15B7 1.5L SOHC Engine)

Degrees BTDC	@RPM Automatic	@ RPM Manual
16°	650-750	620-720

92-95 Civic CX (P05 Chip, D15B8 1.5L SOHC Engine)

Degrees BTDC	@RPM Automatic	@ RPM Manual
12°	650-750	620-720

94-95 Civic Del Sol (P30 Chip, B16A3 1.6L DOHC VTEC Engine)

Degrees BTDC	@RPM Automatic	@ RPM Manual
16°	650-750	620-720

All 94-95 Accord EX/LX (P0A, P0B Chips, F22 2.2L Engine)

Degrees BTDC	@RPM Automatic	@ RPM Manual
13°-17°	650-750	620-720

All 93-94 Prelude S/Si (P12, P13, P14 Chips, H22, H23 2.2L/2.3L Engines)

Degrees BTDC	@RPM Automatic	@ RPM Manual
13°-17°	650-750	620-720

93-95 Honda Prelude Ignition Timing Adjustment

For doing the adjustment on Prelude, you will need a timing light. The car must first be warmed up until the fan turns on. Timing marks for timing light are exposed by removing the rubber cap from inspection window on the cylinder block, by the bell housing. Also, the ignition timing check connector must be jumped. It is located under center of dash. See the drawing below for its location.

Connect jumper wire between the Blue/White and Brown/White wire terminals.

To adjust timing, loosen distributor hold-down bolts and turn distributor housing counterclockwise to advance or clockwise to retard timing. Align the pointer with the Red timing mark.

When the job is done, tighten the distributor bolts to 16 ft. lbs. (22 N.m). and recheck timing.

If it is all OK, remove the jumper from the ignition timing check connector. Reinstall the cap into inspection window on the cylinder block.

94-95 Honda Accord Ignition Timing Adjustment

Adjustment for the Accord is similar to the Prelude described above, with exception that timing marks are located on the timing belt cover itself and the service connector is located somewhere else. It is located under the glove compartment, as shown below:

92-95 Civic Ignition Timing Adjustment

Again, the Civic procedure is no different from the two above. As in the Accord, ignition timing marks are located on the timing belt cover itself. The ignition check connector is located different. You will find it on the right side (passenger’s side) kick panel, near the ecu. Check the drawing below for location:

Here are the timing marks on the 1992 – 1995 Honda Accord:

On the above picture, the red mark is 15 degrees BTDC, while the white mark is TDC (0 degrees BTDC). If colors are faded, you may clean the area from dirt and/or grease and highlight each with white and red chalk, so it shines through the timing light. Remember that the last mark at the right should be the white one (TDC).

 
www.TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Installing a performance chip on 1993-1995 Honda Prelude and 1994-1995 Accord is a single procedure that consists of removing the stock chip, soldering a socket in place and inserting the performance chip on the socket.

Different from the OBD-I Civic and Integra ecus, which you must add some extra parts, the OBD-I Accord and Prelude ecus do have a stock chip that can be replaced, making it simpler in a way, but tougher at the same time in another, because you will need to unsolder the stock chip, which is held with soldering in both top and bottom sides of the circuit board.

Note: This job requires average skills on electronics soldering, but it doesn’t require skills on electronics. You may always bring the computer, the new chip to any TV or electronics shop so they can install the chip, then you just install back the computer in your car. Also, all connections should be verified before and after soldering the socket. Take care not to jump connections with soldering or brake circuit traces by over heating. Notice that there are connections above, bellow and inside the circuit (multi-layered) board that are sensitive to too much heat. Always clean the finished job with a mild solvent like 91% – 99% isopropyl alcohol.

Your car’s ecu is located at the passenger’s side kick panel or lower dash. After locating the computer in your vehicle, remove the bolts that attach the computer to its place and carefully disconnect the harnesses that are plugged to its back. The harnesses can be disconnected by pushing a clip, located on top of the plastic connectors and pulling it back carefully.

This installation is needed only once. After that, it will be a matter of pulling out one chip and inserting any other, every time you want to switch between “Stock” and “Power” modes. These instructions cover all 1993 to 1995 (OBD-I) Honda computers that are listed at the top of this page for Accord and Prelude.

For installing the chip, just find the 28 pin chip marked as “M38256AP-xx” (see the picture bellow). It must be unsoldered and replaced with the 28-pin chip socket, and then the new performance chip must be inserted on it. Make sure that you align the chip so pin #1 goes to the same place of the old chip (lower left corner of the chip in the picture bellow). No other parts are needed on these models. After inserting the chip, just put the ecu back together and reinstall it in your car.

Note: The “xx” after the “M38256AP” is different in every computer. That is the code of the program written in the chip. The picture below is an example of the P0A-A51 (F4). For P0B it will be “F5“, for P14 it is “C8“, and so on. Every ecu has its own code. Even the Prelude’s P13 have 4 different codes, which are “A6″, “E6″, “C2″ and “C3″. On this case, the code depends on the Domestic Market of the ecu. SO, A6 and E6 are Japanese (JDM) and both programs are different. C2 is for the USA ecu (USDM) and C3 is for the UK European ecu (UKDM or EDM).

One good technique of removing the chip, though still requires patience, is soldering all the pins of the stock chip together and fill it up with molten solder, then heating both sides at the same time and gently prying it with a flat screwdriver. This, of course, will require two good soldering irons of 35 watts. Please do NOT use soldering irons hotter than that or it may damage the ecu and the stock chip. The best non expensive and very good quality for this are the Weller brand. Radio Shack’s irons are NOT appropriate for this. Those are more for hobbyists than for heavy jobs like this. Before starting, always spread in all the area to be worked some electronics soldering flux paste to facilitate the job, as it cleans contacts and rejuvenate soldering when heated.

After you finally and GENTLY pull out the chip, you must clean it with desoldering braid so it can be used again whenever you want to go back to stock mode. Otherwise, if you damage the chip when removing it, you will need a copy of the stock chip if you want to go back to stock mode. You can either burn your own or order it from places like http://www.otherdeal.com Just drop a quick message at the contact form on that page requiring what you need. Also, on that page you can pay for the service of installing the socket for you, handing your ecu over the mail.

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Well, the truth is that damage is imminent, but how big, will depend on what gun powder you use.

Before clarifying, first of all, gun powder is solid. Not being a fluid is reason enough to stop thinking on that! Non-fluid components will risk the whole fuel system, specially the capillary size flow parts like injectors, if it gets through the fuel filter.

Haven’t tried that, but if you use regular (old) gun powder (black powder), it is composed of very finely powdered and very intimately mixed charcoal (Carbon – C), sulfur (S) and salpeter (Potassium Nitrate – KNO3). It will separate on a liquid (fuel) and some particles will actually path the fuel filter, specially KNO3 that can be diluted.

That is just part of the problem, because if it makes it through the combustion chamber, the chemical reaction under high pressure and high temperature will be unpredictable.

Potassium Nitrate, which is the part that will mostly reach the combustion chamber because of it solubility at high temperatures, is the oxidant part of gun powder. At high temperature it will liberate one atom of oxygen per molecule of KNO3, boosting the combustion stroke. Yes, possibly more power and possibly in the order of the power given by nitrous oxides (at the end there are plenty of nitrous oxides in KNO3), but with a devastating effect on the engine, like extreme corrosion because of nitric acid formation, damage of the catalytic converter, and a possible complete valve clough because of the resulting Potassium Nitrite (KNO2), to mention a few.

On the other hand, if the gun powder used is the modern smokeless powder, I think that the fuel filter will get cloughed in question if seconds. If it manages to get to the combustion chamber, the same nitrous oxides + nitric acid accident will happen. Smokeless powder is made using nitro-cellulose, like nitro-cotton. Yes, nitrated cotton. It gets worse than that, as it is a double-base powder, meaning that a small percentage of nitro-glycerin is added for a more complete combustion. This complete combustion and the fact that it is a chemical compound and not a mixture as the black powder is, make it burn so complete, that makes little or no smoke and very small solid residue, contrary to black powder. Invisible gasses are liberated from its combustion and that’s is why it is called smokeless powder. At the end some nitro-glycerin may reach the combustion chamber at least.

In any case, it is a bad, bad idea. I though only a child could imagine a thing like that, but who knows. Who ever uses this, will only get a non-running vehicle in a very little time and the damage will be so expensive to fix that maybe will be without car for long.

Sounds like an obvious need-not-to-explain silly idea, but I have often heard things like this, so I better give my two cents for enlightment.

Anyway, keep safe guys.

Copyright: www.TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Start out by locating the engine computer on your car. It is located under the driver’s side dash. You will need to remove the bolts that are attaching it on its place, then carefully pull out the ecu connector by pressing the locking plastic clip on it. See the drawing below for reference on locating the ecu:

Once the computer is out, remove the top cover by taking out the 4 long bolts that secure the cover. Now, remove the 6 bolts that hold the top circuit board. You will notice them as soon as you remove the top cover. The picture below will show the location of the 6 bolts that need to be removed.

DO NOT pull the board up yet! Please, first notice that this board is attached to the bottom board with a flexible ribbon. Flip out the top board very carefully, not to brake the flexible ribbon. Look at the following picture so you have an idea of the attaching ribbon location:

Now, the chip to be replaced, is in the top board and will be covered with a silver colored label or sticker. First, notice the orientation of Pin #1. Write down if necessary, where that pin is facing to, as the new chip must be installed in the same direction. Very carefully, not to damage the circuit by overheating, unsolder the chip and after cleaning the excess flux with alcohol pads and verifying that everything is ok, no broken traces, etc., solder a chip socket (DIP-28) in its place and then just insert the chip in the socket, aligning it in the same way the prior chip was and firmly pressing down after making sure that all pins of the chip are in place on the socket.

It will help a lot if before soldering, you also align the socket mark for Pin #1. That way, it will serve as reference, making any future chip swapping easier.

Put back the board and the computer top cover and then re install the computer in the car. Make sure that the connector harnesses snaps in place when you push it in. Otherwise, some wires might not connect properly, causing problems.

Be careful with what chip you use as there are many sellers offering low quality chips. For example, a chip that we saw in a famous online market, stated that it works on 89-95 models. That is not true! Either 89-91 or 92-94.

A very good chip for this ecu is sold at:

http://www.OtherDeal.com

These will really work for 89-94 GT and GTi models. Do not be fooled by its low price. They pull very hard and are made by real professionals. Believe me, once you test one of these chips, you won’t want to drive your car without it ever again.

Copyright: www.TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

The ecu is located on the engine compartment, below the passengers side wiper assembly, as shown in the picture below.

Remove the hood seal and plastic cover over that area and then release the 68-Pin harness connector by pulling the plug end lever, away from the wire harness. This will release the plug so it can be removed from the computer. Now, remove the bolt that secures the computer to the car’s body and slide the computer out. Often, it can be slightly tight, but it will come out.

Once the computer is out, remove the (4) #10 Torx screws that secure the computer cover and gently slide out the heat sink and connector with the circuit board. Take precautions against static electricity by sitting down and grounding yourself by touching the heat sink portion of the computer. This will balance any existing electrical differential of potential.

Some 1994-1996 VR6 computers may have the ROM soldered to the circuit board and will have to be un-soldered and have a socket installed (included). If this is your case, you can either unsolder the chip yourself if you have skills on electronics soldering or take your car computer to any TV or electronics technician to unsolder it and solder the socket in.

Click on image to enlarge

If your ROM is in a socket already, then gently pry the ROM from the socket with a small flat screwdriver. Lift each side little by little until fully extracted and take note of the notch on one end of the ROM and the socket.

When inserting the new ROM, make sure that the notch is pointing to the same direction as the ROM you just pulled out. Make sure that all the pins are aligned in the socket before carefully, but firmly pushing it all the way down.

Now put the ecu back together and reinstall it on its place. Plug back the 68-Pin connector and push it until engaged. Put back the plastic cover and hood seal.

Great real chips for this ecu can be found at

http://www.otherdeal.com

They are very affordable, but don’t let the price fool you. Even though they are low priced, they offer great drivability and power gains fro your VW.

 Copyright www.TechnicalDomain.net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

Be sure that it reads any number starting with “37820″ on its side label, as some automatic Honda’s have a separated transmission ecu that starts with other numbers. Below is an example of the engine ecu of a P04 ecu. Note that it begins with “37820″.

Richard

www.TechnicalDomain.net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

To take it out, you must remove the glove compartment by gently disengaging it. Also, 2 bolts at the bottom of the glove compartment must be removed along with plastic plugs in the same area at the bottom, that holds a plastic cover.

After that, all that remains are the 4 connectors of the ecu and a support point that the ecu has on its back, covered with a rubber piece. That support point is not tied to anything. Just to move it backwards will loosen it. The four connectors can be disconnected from the front, through the glove compartment hole. Just push the plastic clip of each connector with your thumb, while carefully pulling it back. Don’t worry about taking notes of connectors order, since each one will only fit on its right place.

Good lock guys.

www.technicaldomain.net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches:

After publishing our article about IAT resistors, many people have been requesting related information not included in the mentioned post. Here we are including some
of that info.

The original article may be accessed at:
http://qcwo.com/technicaldomain/?p=64#more-64

NOTE: For easy calculating the resistor you need, just use the online resistor color code calculator: Resistor Color Code Calculator

What does “IAT” stands for?

IAT = “Intake Air Temperature” sensor. On some vehicles, the info of this sensor is very relevant, making considerable changes depending on the value present on this sensor, while in other vehicles it will cause very small changes.

What is the resistance of X model?

Honda IAT:

BMW IAT:

Toyota IAT:

We don’t have the info on the Toyota Corolla handy at this moment, but below you will find how to identify the connection of the iat from the maf sensor. That should be enough for doing some simple temperature tests as described in the first published article about this. Just search for “IAT” on the form at the top of this page or look at the link elsewhere at the beginning of this article.

As you will see in the image above, the pinout seems to be inverted. This is because the reference is taken from the harness connector terminal and not from the MAF connector terminal. Only two wires (4 and 5) connect to the internal IAT. They are; Yellow with a black stripe and Brown (or Orange in some models). Remember that the IAT has no polarity and it can be connected without taking care of that.

Hyundai IAT:

Where can I find the IAT sensor?

IAT sensor for Honda Civic:

Below is pictured the location of the Honda Civic and Integra location of the IAT sensor. It is right after the intake air hardware, at the beginning of the plenum. This is a two-wire connector.

IAT sensor for BMW 325i:

The BMW manual for the IAT sensor location is very simple and do not provide location pictures. They are describes as follows:

92-93 BMW 325i: “on throttle body assembly, behind throttle valve switch”

93-95 BMW 325i: “on left side of engine” (Dohh!)

IAT sensor for 2004-2005 Corolla:

You will find the MAF / IAT installed in the incoming air path, right on top of the air filter on the 2004-2007 Toyota Corolla. It has a 5-wire connector.

These are based on search statistics. Any other model you wish to be added, please just requested below in this page’s “comments” area.

Thanks for reading,

Richard

(C) Copyright - TechnicalDomain.Net

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

Website's recent related searches:

————————————————-

Question

————————————————-

Dear auto-motivo,

can you provide me with the shipping tracking number when available, and i was also wonder if it would be possible to not solder the socket directly to the ecu motherboard but rather solder wires to each pin hole after original IC is removed and connect those wires to the socket that is located in a easier to access location like say in the bottom of the center console for easier chip changing or would the resistance of that length of wire interfere with the chip.

94 – 95 Honda Accord EX 2.2L Performance Chip P0A ECU

- JoEllen

————————————————-

Answer

————————————————-

Hello JoEllen.

I apologize for the delay. We had a technical problem when preparing your item last Friday and it was the last one. Fortunately, we are receiving new merchandise on Monday, so your item will be shipped then. Again, I apologize for this, as we currently ship the same day.

About your technical question, if the chip is wired from any remote location, other than mounted on the socket on the board, the resistance offered by the wires is not to be worried about, but for the possible electronic noise being picked up by the wiring as if it were 28 separate antennas (28-pins). Electronic noise may lock the ecu or make it behave erratically.

If you wish to do so, you should use parallel wiring, like the one used for the hard disk or CD-ROM data connection (IDE), making two separated harnesses of 14 pins each one, plus, it must be shielded and the shielding must be connected to ground on the ecu. For example, heavy aluminum foil can be neatly rapped around each of the two resulting harnesses, and then, both must be securely (flawlessly) connected to ground.

On the other hand, if your idea is to switch between “Stock” and “Power” chips, or just two different chips, a dual chip would do the job better and you will be able to choose between programs with the flip of a switch. This will only work if it is going to be chosen between two programs only. If it is to be switched among more than two programs, this approach won’t work.

For this you will need a dual chip which is, a double capacity chip with two programs accommodated on it. For example, your ecu uses a chip of 32K, and a dual chip will have a capacity of 64K, making room for two programs. Then it will be a matter of switching the higher memory address bit between ground and +Vcc to choose which one of the programs to activate.

You will find more details in the link below. If you are interested, and the programs are “stock” and “power”, I can send you the dual chip, where the default program is the power one, that will be active in case you finally decide not to do the wiring for the dual chip, which really is very easy and will need much less effort than wiring the whole chip (it is explained in details in the link at the end of this message (our blog).

The only thing with a dual chip in Honda cars, is that in most cases, the engine has to be turned off, flip the switch and then start the engine again so the changes take place. Flipping the switch with the engine on, will do no harm, but the program might not switch.

Just let me know.

Best regards,

Richard

www.racingchips.net

Technical Info:

http://qcwo.com/technicaldomain/?p=129

Also Interesting…

• IAT Resistor Mods vs Performance Modules vs Real Chips
  IAT Resistor/Modules Vs. Performance Chips

  What are those infamous…

• More Information on the IAT modification – Follow Up
  

  After publishing our article about IAT resistors, many people have been…

• EWS Deletion Chip
  UPDATE:
  One of our customers, Jerryvan Rosado, sent us some valuable infor…
• Installing a Honda P28 ecu chip
  How to install a P28 chip.

  While this covers the P28 USDM ecu, the p…

• Installing a Chip on the 1993-1995 BMW 325i/525i
  
  This document is about installing a performance chip on a 1993 – 1995 BMW…

Website's recent related searches: