Topic: idle problems

[bigbelman2009]

to start off, my jeep use to have a weird missing problem. i changed a bunch of sensors and plugs like 5 times. turned out to be the manifold gasket. now to my current problem. ever since i changed the tps it has been idling very strange. my second tps would idle under 500 when i would first start it up, then go around 700-750 when it was warm. now on my third tps it idles around 800-950 which seems a little high. should i try to get a new tps? and what is the idle of a 89 2.5 suppose to be around?

[jfrabat]

to start off, my jeep use to have a weird missing problem. i changed a bunch of sensors and plugs like 5 times. turned out to be the manifold gasket. now to my current problem. ever since i changed the tps it has been idling very strange. my second tps would idle under 500 when i would first start it up, then go around 700-750 when it was warm. now on my third tps it idles around 800-950 which seems a little high. should i try to get a new tps? and what is the idle of a 89 2.5 suppose to be around?

Iam a rookie mechanic myself, so dont give too much weight to my opinion, but if it is idling under 1K, and it is not sputtering, I would not worry too much about it.  In my YJ, the idel speed changes (specially with outside temps), and it goes from about 650 or so to about 950...

[cletz97]

my tj has an idling problem also
when i start up cold its like 1k
then after its warm and when i stop moving and im not in gear my car starts to go really low and gets close to stalling out but never does
it just bounces from 4-6 hundred rpms
any ideas?

[chardrc]

my tj has an idling problem also
when i start up cold its like 1k
then after its warm and when i stop moving and im not in gear my car starts to go really low and gets close to stalling out but never does
it just bounces from 4-6 hundred rpms
any ideas?

mine did that when i had a big exhaust leak, but could very well be something else. and any idle below 1k i conceder to be good (as long as its not about to stall / missing).

[Matt vs YJ]

The TPS on an '89 needs to be calibrated when installed, unlike '91+ which is plug and play. Did you do the calibration?

The computer will make mine vary between 600 and 800 rpm when fully warmed up.

[bigbelman2009]

i read something about the calibration but i don't know how. anyone wanna tell me how?

[Matt vs YJ]

i read something about the calibration but i don't know how. anyone wanna tell me how?

Here's the basics (Applies to '87-'90 2.5L YJs):

You'll need a digital volt meter to do this. All measurements are made with the TPS plugged in (you need to poke through the insulation with the tip of the probes).

There are 3 wires going to the TPS marked A, B, and C going from the top to bottom.

Wire A is your output voltage, B is ground, and C is input voltage.

With the key ON and engine OFF, check for 5 volts input voltage (Positive lead on C, negative lead on B). If you read 5V then move the positive lead of your meter to wire C and check the output voltage. You should read between 4.6 volts and 4.7 volts with the throttle fully open. If not, then loosen the two mounting screws and rotate the TPS until you get the correct reading.

[Matt vs YJ]

Ok, I can't edit my other post but here's a correction:

With the key ON and engine OFF, check for 5 volts input voltage (Positive lead on C, negative lead on B). If you read 5V then move the positive lead of your meter to wire A (not wire C as I wrote before) and check the output voltage. You should read between 4.6 volts and 4.7 volts with the throttle fully open. If not, then loosen the two mounting screws and rotate the TPS until you get the correct reading.