Hey everyone, been surfing for a while and finally joined because I became the owner of an 86 IROC. I'm an ASE Master Certified Mechanic but don't see many of the old dogs anymore, even though I work at a GM Dealership, I NEED some help. Here's my issue, just bought the car,the car runs great (Even better sideways!) but had a funky idle (Hunting) issue that lead me to finding fried internals in the computer when I checked to make sure the memcal was fully seated, so I put a new computer in and it runs better, idle doesn't (hunt) anymore but it idles high, at least 1500rpm, the previous owner told me he had put a new TPS on it that was from his other IROC that he parted out, I tested it while checking everything else before the computer change, and at the signal wire it read 5 volts at idle and drops as you open the throttle, backwards right? It seemed backwards to me anyway so I put on a different one (that's been in my toolbox for like 8 years) that reads the voltage in the correct direction, (low signal .5v at idle up to 5 at wot). I switched the TPS and the computer at the same time. So now my only problem is a code 22 for TPS signal voltage low, and it idles high, high enough to chirp the tires when you put it in drive. I want to just put a new/correct TPS on it because this one is old and god knows what it came from in the first place? So what I need to know is if anyone else has had a tps read like this, and if its correct and I should just put it back on, or if its wrong and its just some part info/number glitch that the parts stores have, if thats the case I dont want to buy one and find out afterwords that its the same a** backwards thing and I cant return the part, or if anyone just has a known good TPS part number for a 86 305 TPI vin F. Sorry for writing a book guys but I like to be thorough, plus then you don't have to ask me 10 more questions!

So basically what I'm asking is:
Has anyone else had a TPS give backwards data?

Do you have a part number of a know good/correct sensor?

Thanks For any input! Looking forward to being around for a while, I also enjoy volunteering my knowledge when I can!

I attached a pic of the Smoked computer with the lid off, nice huh?

 

You have the wrong TPS.

The correct one is Standard Motor Products # TH37, should be available at any part store. There actually an adjustment for the TPS and the throttle blade angle on these old sleds. Search and you will find the procedure.

 

some of the new TPS's they sell are non adjustable now, they only bolt on in one position so if it works properly you can't screw up putting a new one on


and that is the most burnt PCM i've even seen lol

 

Thanks guys! Yeah I know how to adjust the TPS and stuff. I have it set at .54 at idle. As far as the fried ECM, I totally didn't expect to see that either, but at that point you cant bother chasing any more ghosts under the hood when you know you have goblin sh** in the ECM! Hahaha