91_XJ_Dude

so did a CEL test in my '91 Cherokee with a 4.0L HO. found that the only code that comes up is for a TPS. would this cause a low idle and stalling problems? if so how easy are they to change out. ive heard stories about the torx screws stripping out.

billfrank85

Mine has two torx screws + the electrical connector, it's on the throttle body. The heads on mine are stripped.

91_XJ_Dude

*bump*

clacker

when i replaced my TPS, the new one came with new torx screws

ken72

I changed mine in the parking lot at autozone. Easy fix. If it has never been changed then I dont see why the screws would be stripped. Just make sure you use the right size and you are good. Disconnect the battery first. You can reach it without even taking the throttle body off. If you can fit the torx bit to a ratchet with an extension you will get more leverage on them and you will not strip them.

oh and yes it can cause some stalling issues. Mine were caused by cold start ups.

91_XJ_Dude

yeah well i tried at one point to change it and the torx screws stripped easily. any trick to getting them out?

ken72

See if you can force a small flat head in and put as much pressure as you can against the screw while turning it or try forcing an allen wrench in it. There may be enough bite in it still.

91_XJ_Dude

yeah i could try that. i think i will wait till i go to put a new battery in her too. that way its already disconnected. lol.

ken72

if that does not work you may be forced to pull the whole throttle body and try to use some needle nose pliers to break them loose. Or try removing them after driving a little to heat the screws up. That might help also.

91_XJ_Dude

well pulling the whole throttle body is something i definitely dont wanna do.

dukie564

before you go buying a new one, test the existing one

HOW TO TEST

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

91_XJ_Dude

yeah im not going through all that trouble with meters and ****. im just gonna replace it.

ken72

Hahaha, I felt the same way. I knew it was the problem anyway so there was no need to test it. BTW... I knew it was bad because my mechanic put a tester on it for me and told me it was bad but I already knew that before he told me.