TPS Experts. I have high voltage input.

(1990 I6 AW4)

I asked this question in the post below, but no one seemed to have an answer.
Butterfly Adjustable?

What does a high input reading mean and what are the consequences?

I can get my TPS output(5.54v) adjusted to 82% of the input(6.8v). My ground is 0.02v. There are smooth readings from closed to WOT. All sources (forums, FSM, writeups) say that my input should only be 5.0v at most. Why would mine be so high?

Hate to attempt to answer your question with a smart@$$ question but....

Are you sure your meter is OK? Is the meter battery dying?

If you need a reference to check it -- the red and black on a PC drive power connector is good ref. for 5V

I don't think the slightly high voltage is an issue. The important thing with the TPS is the RATIO of the voltages, or the percentage, which you indicate is correct. I wouldn't worry about a voltage that is within about 10% of spec.

The TPS ratio itself seems good but that hi-voltage tells me that the voltage is not being properly regulated elsewhere. Saw your ground leakage but just for fun, I'd add that jumper ground anyhow.

ECU depends on a 5v reference voltage although I do not know if your voltages are out enough to throw it off. Sorry I dunno if the ECU itself does the voltage regulation or an external circuit does that. FSM should indicate this as well as acceptable voltage range.

I'd grab my FSM + meter & check voltage inputs to the ECU & trace back. If ECU inputs are listed as only 12v into ECU w/ 5v outputs on some of the pins then voltage regulation is internal. (Pretty sure this is the case but check your FSM to be sure.) If 5v regulation is internal, borrow a spare ECU & swap it & recheck voltages.

HTH

The 5v requirement is only approximate. You are within the variance spec range I believe. Usually they seem to be 4.7 or so on this board. Mine is about 5.3. As said the ratio is the critical item. Greg