I have always had trouble starting my car and had to put up with crappy off idle acceleration when cold. It has always seemed a bit screwy however I checked the prom chip in the car and it says ABWN. Is this the right prom for my 1989 Iroc-Z 5.0l TPI Auto. And even if it isn't will it make a difference to replace it with the correct prom. I was just wondering because the ECM has a remanufacture sticker on it.

 

Hello your PROM ABWN is off a 1987 Auto 5.7/TPI according to:
https://www.thirdgen.org/newdesign/faq/thirdgen.shtml
87 5.7-8 A/Trans(M39) Fed, 3.27(GW6) 16068654 8656ABWN


Below are the correct ones for your application.
1989 5.0-F A/Trans(MD8) Fed, 2.77(GH3)_ 2.73(GU2) 16129297 9298 ANYH
1989 5.0-F A/Trans(MD8) Calif, 2.77(GH3)_ 2.73(GU2) 16129383 9384 ANYZ


Hope this was helpful and let us know if the problem was fixed.
CC

 

The PROM is based on axle ratio, and FED or CA emissions too. Go to www.acdelco.com and click on automotive parts(at the top), then key in your year, make, model and engine, go to the 'engine' category, then to computers/PROMs. You'll get a list of several PROMS for that car. You should be able to find yours if it's the factory(Delco) PROM.

And if it's a Delco, it'll say 'Delco' on it, then it'll have ABWN or some other 4-letter abreviation under the name, and then it'll have a 4-digit number under that. It's all very small, obviously, and it should match one of the PROMs on the list. Mine for my '87 matched.

But as for your problem, I don't know if it's PROM-related or not. It doesn't sound like it to me--but apparently there's a good chance that it is since the above post says it's not the one for your car. Nice recovery, huh, lol?