Troubleshooting a Honda P28 Chip Installation
Installed a performance chip in a Honda P28 and it is not working? Having problems?
Don’t worry. It is more common than you think, as many people choose to install it their selves, even if they have no experience with electronic parts soldering / desoldering and these ecms, even though small and somewhat basic, still are computers with sophisticated and sensitive circuits which are physically fragile. Once in a while, even professionals face some problems, so here are some basic methods to troubleshoot your installation.
This will cover not only the P28, but the P05, P06, USDM P30, P72, P74, P75 and OBD-I PR4 computers as well.
First things first
The most common problem is that the engine won’t rev more than 4000 RPMs after the installation of the chip and check engine light will be turned steadily on also. This will be accompanied by a too rich mixture smell. Some others, show a different behavior like VTEC not activating (on VTEC engines), rough idle and difficulties starting the engine.
Before doing anything, please check that both chips, the EPROM and the latch (74HC373), were inserted in the right direction. If any of those is backwards, correct it and do a test. Note: It is possible that the inverted chip or chips got damaged, needing replacement.
If chips were inserted the right way, the next move is to check if the ecu is still working when put back to stock mode. To do this test, just remove (unsolder) or cut “J1″, which is the jumper that is instructed to solder in when installing a performance chip, and do a test starting the engine. Note: Removal of any other of the installed parts is NOT necessary for this test. This test will rule out the possibility that the ecu got damaged somehow, when the installation was performed.
“J1″ jumper tells the ecu circuit whether to use the internal (stock) program or use the code existing in the installed chip (external program). The ecu will be in stock mode when “J1″ jumper is cut (opened). In that mode it will be using the internal program, which is embedded in the microcontroller itself (OKI 66207). On the other hand, when this jumper is connected (closed), it will force the ecu to use the external program, which is written in the installed chip. So, if when opening J1, everything goes back to normal and problems no longer show, then the problem will be one or a combination of the following 3 causes;
- The installation wasn’t done right
- The chip installed is not compatible with the ecu (wrong program)
- The chip is damaged
If the problem persists after doing the “J1″ jumper test, then somehow, the ecu circuitry got damaged during the installation. For possible causes, keep reading.
How to check the installation
Accidental jumpers or short circuits
The first thing to check is the soldering. You should check for accidental bridges, jumping contiguous pins or connections of the installed parts. Do this firstly by inspecting it visually using a magnifier glass. If nothing is found, then you should use an ohmmeter to check for continuity between every pair of contiguous pins. This is important as the circuit board is a multi-layered one, meaning that it has connections above, below and in between its layers, making some connections not visible. When too much solder is used, it tends to absorb it through the integrated tubular connections that join all the layers and possibly accumulating in excess, jumping two or more points. So, if any two contiguous pins of any of the installed parts shows a resistance reading of less than 1 or 2 ohms, then somehow those two connections got jumped by excess soldering or metal debris.
Broken Connections
The other thing to check is possible broken connections that often happen on these jobs due to overheating when soldering. This computer circuit boards are VERY sensitive to excess heat and this accounts for the majority of the problems that show after an installation.
If a connection was broken during installation, it will be between the chip, the latch (small 74HC373 chip) and the MCU (64-Pin microcontroller unit), because that is the area involved on the job.
Below is a chart that will help you corroborate all involved connections. All the connection should measure continuity (less than 1 ohm) with an ohmmeter or continuity checker. Any reading over 1 ohm is indicative of a faulty connection. If any of the connections displayed in the table fails the continuity test, it must be corrected before going further with the test. Do so by checking the circuit to see if the connecting trace is visibly broken so it can be fixed by soldering. Otherwise, just run a thin insulated wire, soldering between both points that failed. The wire should be kept as short and close to the board as possible. This Will prevent it from picking or generating electronic noise.
Before the chart, there are two pictures. One identifying the involved components and the other, showing a guide for identifying the pin numbering on every respective chip.
Involved components location:
Pin Identification of involved chips:
Connection test chart:
|
EPROM Check Points |
|
|
EPROM Pin# |
Connects to: |
|
1 |
#20 of Latch |
|
2 |
#13 of MCU |
|
3 |
#15 of Latch |
|
4 |
#12 of Latch |
|
5 |
#16 of Latch |
|
6 |
#19 of Latch |
|
7 |
#9 of Latch |
|
8 |
#6 of Latch |
|
9 |
#5 of Latch |
|
10 |
#2 of Latch |
|
11 |
#3 of Latch |
|
12 |
#4 of Latch |
|
13 |
#7 of Latch |
|
14 |
#1 & 10 of Latch |
|
15 |
#8 of Latch |
|
16 |
#18 of Latch |
|
17 |
#17 of Latch |
|
18 |
#13 of Latch |
|
19 |
#14 of Latch |
|
20 |
R54 (at left side) |
|
21 |
#11 of MCU |
|
22 |
#23 of MCU |
|
23 |
#12 of MCU |
|
24 |
#10 of MCU |
|
25 |
#9 of MCU |
|
26 |
#14 of MCU |
|
27 |
#15 of MCU |
|
28 |
#20 of Latch |
Pin#11 of the HC373, connects to Pin#22 of the MCU
When “J1″ Test Fails and all connections are good
If “J1″ test fails and all connections on the table test OK, we have seen that sometimes the latch chip (74HC373) goes bad by overheating when soldering it or by static electricity. Also, as mentioned before, backwards insertion of any of the chips can damage either one or both, but being this one the more susceptible to such problem.
The less possible but has happened before, is the MCU going bad for the same reasons.
The procedure then, is to replace the 74HC373 first as it is quite inexpensive (about $2.00) and do a test. If problems persist, then it is best to replace the ecu, as a spare MCU is hardly found, adding to this that it is a discontinued product. Also, replacing it will take a greater effort than the the whole installation job and might really ruin the ecu, loosing the money spent in that part anyway.
FAQ
Q – Will a chip with an incompatible program damage my ecu?
A – No. The ecu will activate the check engine light steadily and go to protection (limp home) mode to avoid engine damage. To achieve the purpose of protection, it won’t allow the engine to rev more than 4000 RPMs and fuel mixture will go very rich to avoid destructive lean conditions.
Q – I have had many problems buying chips like these on eBay and other places. Do you know where to buy a real good chip?
A – Yes. We know about problems with eBay. Most chip sellers don’t know about mechanics or racing, neither programming. The ones that sell a chip that doesn’t fail, are selling just the same copies of the same chip. Nothing new and those chips are only fairly good. We highly recommend the chips found on the link below. They are tested and will make your car pull real hard:
In that web site, you will also find the service of chipping your ecu very affordably, in case you don’t want to, don’t have either the tools or experience, or didn’t find anyone to do it for you.
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Nice Site layout for your blog. I am looking forward to reading more from you.
Tom Humes
Thank you Tom. I’m glad you liked it.
Thanks for reading.
I did all that is said here and still having problems, so i conlcude it is the chip i bought from ebay, as cutting j1 makes the car works good.
Hello. If cutting “J1″ solves the problem, definitely the problem is the chip. It may be that the chip program is not compatible with your ecu, it may be that the chip architecture is not compatible with your ecu electronics, it may be that the chip electronics are damaged (static electricity or other factors) or it may simply be that the chip is garbage.
Please, before buying chips on eBay, make sure that the seller knows what he or she is selling. Make technical questions. Simple answers like “yes” or “no” to your questions is simply not acceptable. Many chip sellers on eBay don’t know a thing about electronics, programming, mechanics or even driving safety.
Be smart and be a step ahead.
Regards,
Richard
I forgot to mention some history about chips.
Some time ago many forums on the INTERNET that shared technical information about modifying chips for different car models, used to post the modified file along with the original file and all information about it, including algorithms to accurately make the calculations for customizing chips. Then the eBay boom began when forum users, specially “newbies” started to download the modified files (prototypes from forum users)and using them as good and completed, to make and sell chips on eBay. As it should be expected, many chips that were sold this way, failed and some caused damage to engines. When people started to complaint on eBay, the word spread out and Forum administrators started to restrict users because of this behavior and some of the admins even prohibited sharing modified files at all in their forums. Those chips are still on eBay and are now sold for cheap in an attempt to sold the greatest quantity possible without caring about customers.
To prevent from being banned or avoided by buyers, they started putting bogus information on auctions like “We have been chipping ecus since xx year, and we know what we are doing”. But facts go further than words and people realized otherwise, but only after having spent their money in such a garbage.
The real problem on eBay are buyers. People leave feedback before even trying the product. Only a few were brave enough to test first and then give feedback. That is why there are many feedbacks that state “nice looking”, or “fast shipping” and many more that doesn’t speak for the product, but for the service.
A few also tested the chip and felt something, but didn’t realized that it was the “placebo” effect, fooling them into thinking that it is a good product, even when the car ran the same as before. Yes, many stock chips were and still are being sold on eBay as performance chips. This placebo effect was also caused by the infamous IAT resistor in most cases. This happens often to people that have not tried any chip before and didn’t know how a real good chip should feel.
About the IAT resistor, many buyers had no other choice, as these resistors and fake modules, are offered to every car, even new ones, while real chips are only available to few models and are limited in Manufacture Year, since most car computers from 1996 and up (OBD-II) don’t use those chips in their circuits. A sure sell was obvious.
Other chip buyers, were not fortunate enough and their cars didn’t even start. Some started, but blew their engines when test driving because of a hard knocking in the pistons caused by a too advanced ignition timing and a too lean AFR mixture induced by the chip. Of course, the seller didn’t know about this, so If you would ask him, they would have said otherwise.
About Honda, many sellers say they sell “Mugen”, or “Spoon”, “JUN”, etc., but if you call every one of the mentioned Companies, they either say that they didn’t make those chips or that they don’t make chips for those cars or applications. Some of those Companies complained to eBay and eBay forced sellers to change the name of their products as they were violating the VeRo rules by copying a trade mark. That was the birth of M-Gen, instead of Mugen for example. After some years, I guess that those Companies got tired of trying to eradicate those trade mark infringements because once in a while, you will see their trade names again on eBay for chips.
I think part of this began for Honda chips when someone published a list of chip files that were sold by a Malaysian guy named Richard Wong. They advertise chips that will tune your car like “Mugen” or “Spoon” do, but those were not from such Companies, but an adaptation of some “supposed” read codes from them. Whatever happened, those Wong’s chip files were intercepted by today’s eBay sellers (with exception of a few of them, like Auto-Motivo) and are the same chips that have been sold as of today, though each one claim different and add supposed attributes. The only attributes that they can really add are VTEC change over and revlimiter in many cases, thanks to free softwares that have been freely distributed by a few talented people that were kind enough to let everyone have it. Still, today exist many parameters of chips’ program codes that are still not understood in full or at all, either because lack of knowledge or special tools, or simply because of lack of interest, so even those free softwares are not the complete solution.
Any question, please post in the “comment” area below.
Richard
wat is yo fb name?
It took me a while to search online, only your site explain the fully details, bookmarked and thanks again.
- Laura
HI,THERE, I WAS WONDERING IF THERE IS ANYWAY THAT YOU CAN HELP OR GIVE ME DIRECTIONS ON HOW TO INSTALL A PR4, PERORMANCE CHIP, FROM WHAT I HAVE RADE, THIS IS WAY TO COMPLICATED FOR ME TO DO, I HAVE NO KNOLDGE OR IDEA ON WHERE TO START, ITS LIKE PUTTING A DOG IN A ROUND ROOM AND TELLING HIM TO GO AND PISS IN THE CORNERS.. PARTTEN MY ENGLISH…. IF YOU COULD PLS HELP THAT WOULD BE GREAT THANX
Hello John.
There are two different PR4 ecus. Both are for Integra, but there is the OBD-0 (1988-1991) version and the OBD-I (1992-1995) version.
For installing the OBD-0 version, it is just like installing the PM6 chip. Just look for a 28-Pin chip (EPROM), marked as M38256, made by OKI. That chip is the one to be replaced with a 28-pin socket and then you insert the new chip on the socket. No resistors, capacitors or anything else needed on that ecu.
The article to that is the following:
http://qcwo.com/technicaldomain/1988-1991-honda-civic-crx-performance-chip-installation
If, on the other hand, it is an OBD-I ecu, then it is like installing a chip on a P75 or a P28. You will need to look for a blank spot (footprint) on the circuit board, marked as “27256″. There you will need to install the socket and then the EPROM on the socket. You will also need to look for other 5 footprints for installing parts.They are C51, C52, R54, J1 and 74HC373. Those are for two capacitors (C51 and C52), which may be .01uf to .1uf, a resistor (R54), which may be form 1kohm to 10kohm, a simple jumper (J1), which may be a small piece of small gauge wire (for enabling the external chip) and the 74HC373 latch IC, which is a 20-pin small chip for interfacing the new EPROM to the MCU.
An article for that one is in the link below:
http://qcwo.com/technicaldomain/installing-a-honda-p28-ecu-chip
Note: in some Integra ECUs, like the P72, there is no need for R54.
Best regards,
Richard
http://www.OtherDeal.com