Thread: TPS Problem

I've had a low stumble surging idle for awhile on my 97 b14 Se-r with a high port sr20. A while back I check the voltage through consult and the voltage came up .36v throttle closed. Today I tried adjusting the tps using a brand new volt meter and with the throttle closed and the engine off but ignition on the on position and warmed up to operating temp. From the connector on the tps hardness connected I check the center signal terminal wire I was getting a range of low voltages from .37 to .63v and giving it throttle the voltage did not change at all as it's supposed to be 5 volts with the throttle open. My question is could I have a bad tps? And does it matter whether I'm using a auto tps or a Manual tps?

The auto and manual sensor shouldn't make a difference. I'm using and automatic TPS oN my VVL motor. You could either have a bad connection somewhere in the harness or maybe you didn't have a good enough connection when you tested it.

I'll give another check to today again. I've never really messed with the harness before or cut into it and the terminal c on the tps connector which is the power to the tps is getting the proper 4v above plugged in and running. I did notice yesterday day that when I did disconnect the tps it ran a little better.

That is usually a good sign of a bad sensor. The same thing will happen if your maf is bad. If you unplug a bad maf you will usually hear the car idle better.

You rarely ever see full reference voltage on a TPS even at WOT. I would look for .35v to 4.7v. If you see too high of voltage on the TPS signal you may see a decrease in power. I've logged some tunes where my TPS closed voltage was around .48v but WOT was too high and you could feel the ECU pull timing. I backed the TPS off a bit and the flat spot was removed. It seems like your TPS is where it should be. But if you suspect the TPS is your issue, try driving with it disconnected. If the engine runs perfect, then suspect a bad TPS. If it runs worse, it's likely something else. The TPS is a feedback sensor and isn't used for the normal operational functions of the engine. The ECU does make adjustments when it's there, but they are on par with O2 sensor feedback. They rarely have driveability issues, though in some cases it can cause a few tiny problems.

http://se-r.net/engine/wc_hp_trick.html
Not sure if that's useful at all to ya. Thought I'd put 2¢ in...

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Right. Coheed but shouldn't the voltage change if I give throttle? Today I checked the tps voltage after warming up the car. I shut it off then put it on the on position. I checked the voltage and it said .48v. I then turned the tps as far back as it could and the voltage didn't change. It only changed .02 up or down of voltage. I then turned the tps as far forward as it could and the same thing. I gave it full throttle and the voltage didn't go up. It stayed around .46v to .50v. And that's at WOT as we'll. I drove the car afterwards and the car did have the rpm's there. Ive never had an ecu problem or a problem with the harness at the tps. It's actually getting the correct volts at the bottom terminal which is the terminal C on the manual. So I'm suspecting a bad tps. Would or should the engine run and idle with a bad tps?

Sounds like a bad sensor. I only have experience from my dodge dakota but I know they just do crazy shit when they go bad. If you aren't able to pass a test on one as the procedure is written, more than likely it's a bad sensor. But check the wires before you buy just as a procaution. There is always a posibility of a short or bad ground or something.

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You can idle with a bad tps. You may get a strange/jumpy idle, but most vehicles will still run...

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If it doesn't do anything its bad.