I have an 88 IROC with a TPI 305. I tried to use an Actron scanner and I couldn't get it to work initially with the cars ECM.

After some investigating I found that the ECM was replaced, but the memcal is the stock 88 part.

In order to use the scanner I played around entering different model years until I got it to work as a 1986 TPI 305 car.

I thought only the chips were different through the years and all the 165 ECM's were the same. Are they different for each model year? Does it matter that my 88 is a 5 speed car and the ECM is from an 86 with an automatic?

 

the ECMs are the same, its the MEMCAL that makes the difference.
a lot of times someone will get a used ECM from the wrecking yard & not swap the MEMCAL out. different years used a different mask in the MEMCAL which may be why you couldn't scan it as a 88. 86 used $32, 87 & 88 used $32B
there are some things that are different between a standard trans & auto trans MEMCAL. off the top of my head, idle speed, iac operation, TCC & timing.
open the ECM up & get the code off the MEMCAL. a search here for the code may turn up what the MEMCAL is for.

 

You're right, the MEMCAL is from a 1986 TPI car. The previous owner said he replaced the ECM, but somehow the 86 MEMCAL ended up in there. Anyway, I know the the MEMCAL is from an automatic trans car as it is a 1986. The thing that concerns me about running this MEMCAL is that the 86 TPI had the 'peanut cam' and my 88 has the L98 cam. Could this be a problem? I will get the correct one eventually, but I hope I'm not hurting anything by driving it this way.

 

i think your probably ok, but i doubt its running as good as it should with the 86 MEMCAL.
check the BLM & INT in the scanner, they should both be around 128.
lower means the ECM is removing fuel, higher means its adding fuel.
you may want to see about getting a MEMCAL for an 89, if you do, unplug the cold start injector/valve.

for around $100.00 or so, you can get the stuff to start burning your own chips.
you can get a better over all running car, & with a little work better fuel mileage.
plus if you ever start making mods, you'll need to be able make changes to the chip to match the mods, something you don't really get from the after market chip makers.
i forgot to mention, you can optimize the chip in the 92 also.

 

The BLM and INT are 128 and everything else looks right, although I do have a high idle issue occaisonally. I have just started reading the chip burning stuff and do plan to go that route in the near future. For now though, maybe i'll just get an 89 MEMCAL. Is the cold start injector the only difference? Thank you for your responses.

 

other than the cold start injector i believe there are a few other minor changes, mostly up dates.
when you doing your own chips, its a good ideal to have a known good stock chip handy, so your not wasting any money by getting one.