I have a problem with the idle on my 1990 XJ. It idles OK until it warms up and then it idles at about 2500. I read the Haynes manual on how to set the idle and it doesnt give me anything for a fuel injected model. Is there something I can check and set?
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High Idle
- Thread starter jeepbub
- Start date
jeepdude10000
NAXJA Forum User
- Location
- LaLa land!
on the throttle body, there is a Allen-head screw u can adjust, Have u checked Ur idle air solenoid?
on your throttle body next to your TPS there is a solenoid or something that has one connector going to it. (front of the throttle body) pull it out (2 torx screws holding it in) and clean it up real nice. i cleaned mine with fast drying electrical spray cleaner and it fixed my idle problem. mine did the same thing where it would get higher and higher as the car warmed up. right after i cleaned mine i was idleing at ~750 rpms at normal operating temp. and it didnt go up. since them the highest i see is right above 1000 rpms. but almost always im at exactly 1000 now. i want it lower but i think there are a few more things i need to fix to get it right.
xjbubba
NAXJA Member # 1524
- Location
- santa barbara, ca
High idle on the 4.0l engines are frequently do to a combination of a dirty throttle body and AIC (air idle control) solenoid. The AIC is nothing more than a computer controlled vacuum leak, so also look to split rubber hoses and bad gaskets as a cause of high idle . Remove the throttle body from the manifold and thoroughly clean it with a good carbon remover. Make sure you clean the seat for the AIC plunger--this is generally the culprit, as bits of carbon on the seat or plunger will keep the plunger from seating. Also clean the end of the plunger on the AIC, being careful not to turn the plunger.
Install a new throttle body to manifold gasket when installing the throttle body.
Install a new throttle body to manifold gasket when installing the throttle body.
You mentioned. It idles normally cold, then idles up as the engine warms up.
For this reason, I'm betting you an manifold leak. Either your intake/exhaust manifold is loose or the gasket is failing.
Here's a link that provides additional information on general high idle issues.
http://www.naxja.org/forum/showthread.php?t=81838&highlight=High+idle+issues
Hope this helps,
Kent
For this reason, I'm betting you an manifold leak. Either your intake/exhaust manifold is loose or the gasket is failing.
Here's a link that provides additional information on general high idle issues.
http://www.naxja.org/forum/showthread.php?t=81838&highlight=High+idle+issues
Hope this helps,
Kent
