Okay, So I recently swapped over from a 305 TBI to a 305 TPI, I swapped out the TBI engine for a TPI engine. I have a 305 TPI ECM running it and it still wants to stall and cut out. Also has a ruff Idle. I made sure MAF is good and everything. But I came to the conclusion that it may be something with these to wires that are not connected to anything. I know they have to do something but I couldn't figure out what they are for. They are from the wiring harness originally that had the TBI, it's from under the passanger dashboard under VIN E, Wires B(Pink/Blk) [the one on the right] and G(Pink/Blk) [the one on the left]. Help? I need to know what they do/ what they are for and where the are supposed to be connected?

 

Mitchell on demand doesnt give connector views for your car. Im not sure about the connector number but I think it may be C105? Id have to look at my factory manual to be sure. It ties into the engine/ECM harness close to the ECM. The wires in the photo dont look pink/blk. Pink/blk on GM is ign+. If thats the connector im thinking of, pink/blk wire would be ECM ign. The car wouldnt run at all with ECM ign disconnected. I assume you installed the TPI harness with the engine. Does it have a connector that looks just like this one? How did you power the TPI ECM?

 

They could also be the injector ignition circuits. I suggest finding a factory digram for the 89 TPI IROC and matching the wiring on your vehicle to whats in the manual. The Mitchell diagram may help you and All Data may have a better one. These programs should be available at your local library and will let you print pages.

 

send a PM over to Pocket (he's usually hanging around in the LSx forum here). He's got a ton of wiring info and has been a huge help in my wiring questions. If someone's got the pinouts, its gonna be him