Iac? Tps?

[coach9119]

Which? Problem is random racing idle. Sometimes as high as 3k, but mostly around 1500. If I disco the vacum hose to the EGR, the idle snaps back to normal. I replaced the EGR when I first noticed this, so it's not that, but it's something that's affected by the the vacum system.

I cleaned the throttle body a few weeks ago, but in place not on a bench.

Andy
1990 4.0

 

[jneary]

the early jeeps had tps problems for that, if i remember correctly the 1990's may have had a recall, but not positive.

 

[8Mud]

Curious or stupid, I had somebody start mine with the TPS in my hand, with the wires still attached, curious, idled up to around 2-3000 RPM, shut it off pretty quick.
The IAC or the idle motor, is probably pretty gummed up, if you felt the need to clean the throttle body. Could have dislodged some crud into the passage and seat. Pretty easy to remove it and take a look, there is an O ring, twist a little before pulling, with the torx screws removed. Can clean off most of the stuff from the piston with a finger nail, I used a little spray oil to get the rest of the crud off. And some carb. cleaner and tooth brush to get into the seat area. Disconnect the wires from from the IAC, don´t let anybody turn on the ignition with the wires hooked up and the IAC out of the throttle body, mine spit the piston halfway across the driveway (glad I had a spare, live and learn).

 

[jneary]

I wuold check with a dealer to see if your jeep qualifies for the recall, if so this would be a free repair. it all depended on the date code stamped on the tps itself. it may have already performed by now though.

 

[jneary]

its recall 301t, if your jeep was built between 5-89 and 6-6-90 it qualifies for the recall. chrysler can run your vin number and let you know if it has been done.

 

[coach9119]

thanks I'll check on the recall stuff and try and clean the IAC a bit. The recal is on the TPS, right?

I suspect it's just gummed up - when I cleaned the TB it was better for a bit, then started to go again recently.

 

[jneary]

it was a tps recall, as my memory serves me there was also an o2 sensor recall around that time also, check it out.