I was having a hesitation with an 86 iroc with 14k miles. When hooked up to the OBDI and programmed in for an 86, there was no data stream. So thought ECM Bad. The car was built 11/85 and the shop tried setting the OBD in 1985 mode and the data stream appeared. So I know it has an 85 ecm in it. Is it possible it has the 85 cam as well??? How would I find out???

 

My '95 Jimmy was an early build(09/94)so she is OBD1.5 but with the OBD2 connector.I ran into this the first time I connected my scan tool to her.
On the cam the only idea I have,and I don't know if it will help you,is checking the build date of the motor.But then you have to know when they engine plant changed cam style.

 

I seriously doubt your car has the 85 ECM. That means it would have the old ECM, old wiring harness, old MAF & related circuitry and even a different bulkhead hole in the kick panel area. The ALDL communication stream may be similar enough between the 85 and 86 that the scan tool may be able to read it. I've had glitch issues with my own car where I've had to fool around with different year settings to get it to work sometimes.

 

It would be easy enough for him to find out. It would take all of ten minutes to pull the ECM down from under the dash and look at the part number.

 

1985 cam rpm 5000-5500 yellow
1986 cam rpm 4500-5000 yellow

which one do u have

 

Nice Car!!!

 

Even that isn't necessary. When you pull down the 85 ECM you'll see the giant MAF Burnoff circuit piggy-backing it. Speaking of which... you can just look under the hood on the firewall. The 85 will have 2 relays near the brake master cylinder... the MAF power relay and the fuel pump relay. The 86 will have a third relay for the MAF burnoff.

 

I will check it out

 

Just like cdartz said, pull out your ecm and read the number on it. Here is a list that will help you.
Model Year GmpartNo EngineF,Y 1985 1226870 5.0L/5.7LF,Y 1986-1989 1227165 5.0L/5.7LF 1990-1992 1227730/16198262 5.0L/5.7LY 1990-1991 1227727/16197128 5.7LY 1992 16159278 5.7L LT1F 1993 16159278 5.7L LT1Y=Corvette F=Camaro ,Firebird, Trans-AM

 

You are right on. There is a 3rd relay on the 86 that I don't see on my 85. Must have been a scan tool glitch...

Thanks!

 

Something awfully odd... I've got an 85 Trans Am, with the stock 2-6870 ECM, but it has no MAF Burn Off module piggy backing it. It looks like mine is mounted further up into the dash. Is that normal? Or is my car a freak of nature? I've only got the 2 relays on my firewall. Wierd eh?

 

Hey tkr I live in st marys county md nice to see some local peeps on here

 

Sorry for the hijack but my 85 has the big piggyback on the comp. But I only have 1 relay on the firewall and thats the fp relay. I know my maf still works,I actually just replaced it. Any ideas where that relay could be?