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

- Laura

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

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

Thanks for reading.

Tom Humes