Won't idle...

[64chevy]

I'm having trouble keeping my 1989 MJ running at idle. I have changed almost all of the emission vacuum harnesses, new plugs, rotor, cap, wires, fuel filter, O2 sensor... Give it fuel and it runs fine... Any suggestions?? Thanks!

[codymanche]

have u tried to adjust the idle from the throttle body it take a lil allen head i believe

[Geonovast]

Sticking/faulty IAC.

[Bounty Hunter]

2.5L or 4.0L engine?

 

I'd guess a bad IAC controller (idle air control) on the throttle body, a dirty throttle body, or if a 2.5L a bad idle motor.

[comanche12]

we can't adjust the idle. correct me if I'm wrong? try clean the TPS and IAC first.

[codymanche]

just out of curiousity where is that iac located on the 4.0l straight 6?

[Geonovast]

Right next to the TPS on the throttle body.

[bigalpha]

we can't adjust the idle. correct me if I'm wrong? try clean the TPS and IAC first.

 

You can if you adjust the the small allen screw that holds the throttle plate from hitting the TB when it closes. The PO of my truck did this when it stalled on him.

[Lemmon714]

I had an issue with the MAP sense tube from the throttle body to the MAP sensor. It cracked at the elbow going up to the sensor. I replaced the tube and my idle was much better. Might not be your issue, but it is another possibility.

[comanche12]

we can't adjust the idle. correct me if I'm wrong? try clean the TPS and IAC first.

 

You can if you adjust the the small allen screw that holds the throttle plate from hitting the TB when it closes. The PO of my truck did this when it stalled on him.

 

ah alright just make sure since i remember i saw the label somewhere on engine bay said the throttle is not adjustable.

at least remember someone always said we learn something new everyday :cheers:

Right next to the TPS on the throttle body.

 

:agree:

[Bounty Hunter]

It's not adjustable, it's computer controlled, adjusting the throttle stop is an incorrect fix to a problem somewhere else.