billienaj

iTrader: (2)

Curious if anyone else has had tps sensor issues with the tpi engines in the 86 camaros?
I have had to replace tps sensor about once a year i figured due to buying an aftermarket cheap part. however this year the sensor is not taking care of the issue. so i started tracking it Down and found that intermittently the signal voltage my pcm is seeing is .05 volts when i just key on reading with a scan tool. then if i wiggled the plug i could get the correct .58 i set the sensor to when i installed it. so i thought it was a pigtail issue and soldered in a new one. seem to fix it for a while but its back again. i have found when the voltage is too low if i cycle the throttle to full throttle with the key on and then let it back to idle it will then show the correct voltage again. it really seems like a tps sensor issue but I've had two different ones act identical. help please.

Crudsturbo

I don't know but I am having an similar issue, just replaced mine a few hours ago and the old one just a few months ago, mine was fixed by the sensor but its idling high now. Would like some info on where and what to test voltage on. Mine is an 85 z28 with tpi system. I had codes 22 and 33 so I changed the tps which fixed me not being able to drive it. The 33 I've found is the MAF sensor circuit. Is it just a matter of replacing it? Also I've never tested a sensor but i know how to use a voltmeter just need intructions and values.

billienaj

iTrader: (2)

You should have a 5 volt reference on the gray wire. a good grounding the black wire and signal out on the dark blue wire rangeing from .54 volts at idle to around 4.5 /5 volts at wide open throttle. The only thing you wanna be careful of is sometimes by back probing a connector you can temporarily fix a bad connection. so it would test good but not actually be good. that's why its nice to use a scan tool to see what the Pcm is seeing. as well. as testing right at the sensor.

Crudsturbo

So if I plug my scanner up to it I can read the data like I can on my 04 pontiac? I just want to get this fixed because that tps blew too fast.

billienaj

iTrader: (2)

Correct. you just need to be careful because a scan tool can lie to you as well. also you will need a scan tool capable of reading live data on an obd 1 gm which your 04 is the standard obd 2

billienaj

iTrader: (2)

Well I traced down every inch of the wiring harness from the tps sensor to the pcm. I couldnt find a thing wrong with it, but i decided since i've replaced the sensor twice this year already and the pigtail that the only things left are the pcm itself or the wires running from the pcm to the sensor. so i started by running a secondary wire along side the signal wire. i didnt disconnect the original wire just ran another one wlong side it, and spliced and soldered the new one onto the old one at both ends. so far it seems to be good and i did notice my signal voltage at the pcm went up almost an entire tenth of a volt so i have a feeling there was some resistance somewhere in the wire. I only did this yesterday, but i did drive the car a lot yesterday and it was a fairly consistent issue. so lets see how it does. ill keep you posted after a little time goes by and i can see if it continues to be good.

RussellRat

You ever figure out what was going on? I have a similar issue right now. TPS reads a solid .5V at idle, but the scan tool shows a computer reading of a big fat zero until the peddle is pushed. The scanner show the computer TPS voltage eventually get close to 4v, but lags the sensor by .7v or so. The engine also won't idle and dies below 1200 RPM. Hope its just a silly wire.

Anybody else ever notice a difference between TPS voltage at the connector and off a scanner?

billienaj

iTrader: (2)

i actually did find my problem, or at least so far so good. ended up buying an OE part straight from GM. no more problems. you will lose a little most of the time through the wire and sometimes even within the pcm. But .7v is a little high. Honestly it sounds like you may have a slightly different issue. But you may want to try an oe sensor. I know it probably doesnt seem like it could be that, and once you see the cost difference youll probably crap. but its worth it.

RussellRat

Thanks. My problem sort of corrected itself. Don't know how or why, but after over a week of the discrepancy, they two TPS voltages suddenly match. Maybe I reset my computer when it was off the battery?