Have just checked the TPS on my SE'96.

It has a throttle open/closed switch incorporated there with two wires going in. Haynes shows a wiring diagram and according to it there must be total of six wires, three to rheostat and three to the switch but I have only two, is this ok? The missing terminal is corked up with some yellow plastic cork right in harness.

The switch seems to have no continuity between two terminals on the left (close to the TPS assembly center, see terminals 5&6 on the picture) in any throttle position. Can it be a badly mounted TPS thing by chance?

The rheostat resistans differ from what it should be. It's 0.74 kOhm in closed (must be 0.5 kOhm) and 4.35 kOhm in fully open (must be 4 kOhm). Measures made on both cold and warm engines. Does this deviation matter?

Why I'm asking is that sometimes I get idle rpms at around 1500, stable but too high... but sometimes they're just fine.

Please suggest. Thanks a lot!

 

As long as the TPS is giving the proper closed voltage, the idle speed is controlled by the Idle Air Control valve, and the ECU.

 

I don't mind... but the question is how big can that resistanse deviation be on the TPS witout seriously impacting the behaviour? How much impact on the idle speed has the fact that when the throttle is closed, there is (a) no signal from that TPS switch and (b) the resistanse differs from what it should be by almost 40% higher... I guess ECU relies on this info and since there is none or there is some info but it's wrong this is not good. Guess, if the switch always has no continuity (which means throttle is open to the ECU) and resistance is higher (which I suppose is typical for open throttle, too) then my higher idle is expalanable. What do you think?

This is my first experience in getting so deep into an engine so I'm just not sure is everything ok and just needs some adjustment or should I take some care of it? E.g. can that switch be non functional because of the TPS positioned wrong? I know position matters there but no idea how much...

Sorry for so much text... I know I'm boring sometimes