I have an 86 trans am that was swapped to a 350 with an upgraded cam by the previous owner. He also told me that the ECM is an '89. I had a chip programmed by Harris Performance and I'm having bad cold start issues. The tuner told me to get the long term fuel trim data so that he could see what fuel adjustments were being made and adjust the injector settings to correct the cold start issues. I took the car to get scanned today and my mechanic said that it would not communicate with the scanner. He said he's not sure what the issue is whiteout spending a lot of time to track it down but it could be that the ECM is not original or that the engine is not original. I wasn't able to pull the check engine light code either because it wouldn't go into diagnostic mode. If anybody knows anything about what the issue is I would greatly appreciate your help. Just trying to get this car running solid so I can enjoy it

 

Two things - Has the engine harness been swapped over to an 89 as well? If so, some pins on the C220 do not align with an 86.
Second, if this is a MAF car and the ecm ends in '7165 it could be the ecm itself. I have an ecm that works perfectly fine - can run the car, put a new chip in it etc. The only issue is that it will not communicate with a scanner.
If the car is stock except for the ecm change, then I would try a new ecm first.

 

It is a MAF car and it is not a stock 350. It's bored .030 over and has an upgraded cam. I don't know if it is the 86 or 89 harness

 

Ya that is fine - those parameters are going to be defined in the eprom(chip). As I said above, check the service number on the ecm. If it ends with 7165 I would try to hunt down another one or see if you can borrow one as a test.

 

Ok I'll have to check that. What do the numbers 7165 indicate? Not compatable with the MAF cars?

 

What exactly is your setup? Are you running an '86 Tuned Port Setup w/cold start injector on a 350 running an '89 ECM? What did Harris Performance burn you a chip for, the '86 ECM or the '89 ECM, what did you tell him when you ordered it...?

 

'86 tpi with cold start injector delete on an 83 Chevy 350 truck block with a cam. Everything else is stock trans am. I told the tuner that it was an 89 ECM, that it has the cold start injector delete and I gave him my cam specs. That's what he told me he needed to make the chip for my setup

 

for whatever reason our 7165 ECMs are hit or miss. as far as being able to data log one with a scan tool , or laptop. personally , i want to up grade the ECM in my car ,which is also a 86 TPI car with MAF. i just dont, as yet, know where to start . rumour has it , theres a guy on here "rbob" that is able to help