Mechanics

HIGH IDLE AND DIESELING

1990 Jeep YJ

Engine Performance problem
1990 Jeep YJ 4 cyl Four Wheel Drive Manual 127, 00 miles

Has a recently installed, newly rebuilt engine. It was running fine for about 6 weeks after install, then started idling high, and shutting off hard (dieseling. Would shake and sputter before shutting off). It does this intermittently. I don't believe there are any vacuum leaks, but don't know for sure how to check. What are the most likely causes?
Avatar
Flyingace22
October 12, 2010.



Its either overheating, throttle plate sticking open and idle speed to high and excessive carbon in the cylinders acting as a glow plugs and ignition timing off

Rasmataz
Oct 12, 2010.
I've only driven it 3,000 miles with new engine, and it has a new radiator as well. Is it really likely that it's overheating, or the cylinders have high carbon deposits? Is it possible that it's the throttle position sensor, or idle speed actuator motor? I've removed the throttle body housing, and it doesn't appear that the throttle plate is sticking.

Tiny
Flyingace22
Oct 12, 2010.
Is it possible that it's the throttle position sensor, or idle speed actuator motor-could be the problem raising the idle speed

Rasmataz
Oct 12, 2010.