Our Community is 940,000 Strong. Join Us.


TPS (Throttle Position Sensor)


creslevi
06-09-2008, 05:24 AM
Replaced my TPS 2/6/08 worked fine till about 6/2/08
When I started car the engine would race, refused to idle and service engine soon light came on, If I unplug the TPS it idles fine, Question Are there any other sensors in that circuit that feed it information, or do you think I was just unlucky enough to get a bad replacement, I got it at Car Quest ?. It's on a 94 Buick LeSabre 3800. Thanks.
Rick

HotZ28
06-09-2008, 10:45 AM
Does the spring return on the TPS seem to be working? Have you tested the voltage on the blue wire with ignition on?

creslevi
06-09-2008, 12:19 PM
Hi
Thanks for the response, Yes the TPS does seem to rotate with the throttle shaft, No I haven't checked any voltage, I have been sick the last month with Heart problem, and can't get out to the garage (too weak) I am driving it with the TPS unpluged, But have no cruise control or passing gear, just trying to evaluate the problem ?.
Rick

happydog500
06-09-2008, 02:06 PM
When I replaced my TPS, it started dong what you discribe 6 months later. I reset the code, it ran fine.
Try clearing the code and plugging it in to see what happens.

I think mine did it twice, once more almost a year later. I just reset the code and it has been fine ever since (couple years?).
Chris.

creslevi
06-09-2008, 03:09 PM
Thanks for the suggestion, as soon as I am able I will give it a try, I think you just unhook the battery a few minutes to reset the codes ?.
Rick

inafogg
06-09-2008, 04:25 PM
i think on your car u would be ok since its OBD 1 but not on obd 2 systems (96 & up)of course using a scanner is always best.Good Luck & hope u recover soon!!

happydog500
06-09-2008, 05:46 PM
Mine is OBD 2, even overnight didn't clear the codes. I had to use a scanner. the other post said OBD 1 is different, so it might work.
Chris.

creslevi
06-09-2008, 06:49 PM
I tryed clearing the code, Service engine soon light went out but the engine still raced
Rick

creslevi
06-09-2008, 06:56 PM
Blue wire is .06v, i forget what it should be ?, This thing has always been soo dependable I am shocked to have this problem in 6 mo after paying a shop $195.00 to read & clear the codes and install the new sensor $80.00, They said they also replaced the throttle body gasket ?.
Rick

HotZ28
06-09-2008, 08:27 PM
Blue wire is .06v, i forget what it should beThat is too low, it should be around .45v and no more than .50v! What is the idle rpm? Are you sure the T/B is closing all the way?

creslevi
06-09-2008, 09:08 PM
As soon as I unplug the TPS it returns to normal Idle speed, What might cause the high Voltage ?.
Rick

HotZ28
06-10-2008, 07:16 AM
You should now check the grey wire, (PCM reference voltage) it should be 5.0v. If this checks out, I would suspect the TPS is at fault. BTW, are the TPS mounting screws tight?

creslevi
06-10-2008, 08:56 AM
Yes the screws are tight, I will try to check the grey wire today sometime.
Thanks Rick

HotZ28
06-10-2008, 11:42 AM
While you are at it, check the low voltage again. Your previous reading does not correspond to a high idle condition. If the reading on the blue wire @ idle position is actually .06v, the engine would probably not run at all.

creslevi
06-10-2008, 11:44 AM
I don't have a grey wire, mine is kinda blue, with engine idling it say's 5.5v with it plugged into the TPS, I shut it off and restarted several times and so far it idles fine, but at this point don't know how long it will last ?.
Rick

HotZ28
06-10-2008, 12:45 PM
The wire colors may change slightly due to heat & age. When new, the TPS GREY wire, is the PCM reference signal and should measure 5.0v-5.5v with ignition on. (Engine does not need to be running) It looks like you are good on that reading. The BLUE wire will show variable voltage from a closed TB position, usually .45v, up to WOT, where it should measure between 4.0v to 4.2v max. The BLACK wire is ground. If your ground is loose or corroded, it could cause the voltage readings on the other wires to be skewed. BTW, notice the edits in my post above concerning the “.06v” reading you said you were getting on the blue wire. Could this have been .6v instead of .06v? :dunno:

Add your comment to this topic!