With the engine running is the TPS voltage supposed to remain constant or does it fluctuate?
Earlier I was out resetting the IAC and TPS, I forgot to remove the probes from the TPS when I started the car and noticed the tps voltage was all over the place, anywhere from .30 volts to 1.90 volts

Is this normal? The car does idle a little rough, not really bad, but enough to be annoying.

Thanks, John

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89 Formula, Maui Blue,355 TPI(used to be TBI) Auto, TES, B&M shift kit, afpr.

 

Nope thats not right if the throttle isnt moving. It should stay within about .01 or so depending on the quality of your meter.

 

Thanks Max.
Heres a little more info, if it helps.
I did some more checking today, I've got good ground, alt output is a steady 14 volts.

With engine not running the 5 volt reference from the ecm is 4.9 volts, but with the engine running I'm getting anywhere from 9 to 13 volts on the reference wire it fluctuates quite quickly. Is this normal? Do I need to replace the ecm?

Would somebody be willing to check thier tps voltage with the engine running so I can compare it to something?


Thanks again.





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89 Formula, Maui Blue,355 TPI(used to be TBI) Auto, TES, B&M shift kit, afpr.