View Full Version : Throttle Position Sensor ?

09-09-2002, 05:30 PM
Does the tps, tell the computer where the throttle lever is ? im trying to get to the bottom of my idle problems.

Mike Puckett
09-09-2002, 07:22 PM
It's supposed to. Check it with a volt meter from the center wire to the negative battery terminal. At idle I think it's around .9v and at WOT around 4.9-5v. Someone correct me if I'm wrong. I haven't checked mine in awhile. It's my understanding that if the TPS voltage is too low it doesn't want to start. I sometimes have to tap the throttle on my 35th to get it to start. I'm thinking that the increase in TPS voltage allows it to fire-up. If it won't idle well and the IAC has been replaced with a new Ford unit, then it could be the TPS sensor. Try this: use an analog(needle movement) type voltmeter and connect it. Move the throttle back and forth and see if the needle moves smoothly or erratically. An erratic or jumpy needle would indicate a bad sensor. Have you ruled out all possiblity of a vacuum leak?

09-09-2002, 07:44 PM
at this point i havent ruled anything out yet. I checked as best i could to see if there was a vaccum hose loose or burned open. i didnt see any. I cant verify whether the iac has been replaced, looks like the factory piece to me.

Mike Puckett
09-09-2002, 09:43 PM
You can remove it and try to clean it as they get pretty cruded up. Spray it with brake parts cleaner as that tends not to attack plastic like carburetor cleaner. It'll be black inside but originally it was white.