I had an 87 Iroc that had a 350 TPI motor in it. My brother gave me a shell of an 85 Iroc that was in better condition, so I decided to do a swap. I had my motor rebuilt and dropped it in. I swapped out the two engine bay harnesses. The one for the injectors and distributor and also the one that comes out of the firewall on the driver side. When i first started the car it idled a bit rough going from a high idle to a low idle back an forth. When I gave the car some throttle it would back fire out of the intake and start to sputter. Eventually it would die. I did notice that the MAF would stay lit even when the key is turned off and out of the ignition. Im wondering if the reason the car falls on its face when you give it throttle is because the MAF isnt reading right and is staying on the entire time, and what might be the reason the MAF stays glowing red even when the key isnt in the on position? Any help would be greatly appreciated, I have been trying to figure out the problem for months now.

 

That is a MAF burn-off situation, and either you did some wiring wrong, or there is
something faulty in the harness itself.. It should only glow to clean contaminates
from the small wire in the sensor itself for a few seconds, then it should stop.

Investigate your burn relay and circuitry, maybe even find a '85 schematic to help.
Im unfamiliar with the '85 TPI setup, as it differs slightly from the late 80's.. However,
it is certain that the car will not run correctly if that burn-off is cooking while it's running.

Double check your work, are you using the ECM from the '85? I hope so.

 

Should also note, and Im not completely sure if the '85 uses the same burn-off relays
as a '88/89 TPI car, but Id look into that as well. If your using that '85 wiring harness,
Id run that car as if it were a 1985 IROC. Down to every relay, ECM, and prom.