Ok, I have read the article on how to convert from 85 ECM to 86-89 ECM, very helpfull...my problem is that I find some contradictive things on the ECM wirering. In my book, They list a wirering diagram that is valid for 85 to 92 F-body, and one for Corvette, which is aparantly wired differently (if you conpare the two diagram). So from what I understand, you could plug any 85 to 92 F-body ECM into any 85-92 F-body harnest without repining. The book is "How to tune and modify Chevrolet Fuel injection". In the book, they have listed "Vin code F 5.0 and 5.7 liter TPI camaro" and then they list the different connectors ( A, B, C etc...) and the pining (ex: B2: Fuel pump signal) with the color of the wire also.
Now in the article (from this bord) it says to repin some wires, but I notice one ecm is out of a corvette and it's going on a camaro. Which I could understand since F-body and Y-body are wired a bit differently (at least that's what they say in my book if you compare the pins). Well then in theory, if you get an F-body ecm, you could just plug it in into your harnest and not repin anything and just add the MAF relays...I'm sorry for the long post, but I'm really confused....

 

The book is definitely incorrect. I cannot say what the specific differences are but I know that you cannot take a 730 ecm and just "plug it in" to an 85 car. Different sensors to boot.

Certain years are easier to repin than others..but it is not a "plug and play".

 

yea I kind of figure that something wasn't right...but I'm more concerned about 165 ecm's...because since Vette ECM's are wired differently than Camaro ECM's and that the article is using a Vette 85 ECM and a camaro 165 ecm as an exemple, and knowing that above fact, I'm wondering if it would "plug in" and all you would have to do is add the MAF relays to your harnest...make sens? just wondering....

 

That book only lists the pinouts for the 165 ecm in f-y bodies.

 

85 TPI systems were in a world of their own. You cannot interchange an 85 ECM with any other harness and vise-versa. For one, the 85's used a MAF burn-off module which was only used that year, starting in 86, the burn off function was controlled directly from the ecm. Now, any 86-89 system is interchangable with the exception that in 89 they no longer used a cold-start injector. So, if you have an 86-88 car, you could put in an 89 prom and unplug the cold-start injector and the car would run fine. Beginning in 90, the system went to speed density. You could use either a 1227727 or 1227730 ecm (which are both identical internally for all intensive purposes) but had different connectors. The 7727 was designed to be installed in the engine compartment. If you happen to be looking for a 1227165 ECM (86-89 TPI), any 2.5L TBI S-10 or S-15 with a manual transmission uses the same ECM.

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1987 Trans Am GTA WS6
-5.7L SuperRam
-TFS Twisted Wedge Heads
-224/230 Xtreme Roller
-LT1 PM Rods
-4L60-E Transmission
-LS1 Aluminum Driveshaft
-3.73 SRD

1988 Pontiac Grand Am
-3800 SFI V6
-125-C Trans
-Stock emissions equipment
Domestic Terrors Car Club Online

 

Are you talking about Mike Davis' article? His re-pinning list is correct. If you have the skills and are careful, converting to an '86-'89 ECM is not too difficult.

I have the book you mentioned. Do NOT use its wiring diagrams. There are mistakes. I have also found mistakes in Chilton's manuals.

Rest assured, you can not make the swap ('870 to '165) without switching some wires. BTW, you don't necessarily have to re-pin. You could cut and splice (solder them!) or add an interposing connector so you could easily convert back to your original ECM.

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-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons