Replaced Throttle Positioning Sensor on a 1993 Olds Ninety Eight and the check Engine soon light comes back on after about a minute or so and it is still coding a 21. No matter what we try it doesn't get any better. Can anyone help with this situation. Have checked the wiring to and from the PCM, tried adusting the sensor, etc. PLEASE HELP!

Thanks,
Zan

Is it running poorly or is it that the light just keeps coming back on? May just need to clear the codes.

TOC Admin
Brando

As soon as the light comes on it throws the engine to a rough idle.

i know what you mean. I replaced the TPS on my car, and actually had to make a spacer to get the right TPS voltage. As soon as the voltage is above 0.2V, it will kick back to closed loop mode.

Try making a spacer for the lever on the TPS sensor, that will space the lever out just slightly, in turn raising the idle voltage for the computer. This solved my problem.

What did you use for a spacer? I understand what you mean but can't come up with anything to use. Thanks for all the help!

Zan

I know it was tough for me aswell, but I took the sensor off, and used an exacto knife to cut a piece of electrical tape to the right size (like an 1/8" spacing). I stuck it back on, and then was able to rotate it to the correct position.

If you have access to a multimeter, try and get the idle voltage to roughly 0.4V. This should make the computer happy, as long as the TPS sensor is in good repair itself. I expect this to be the case. Let me know how it goes!