1990 XJ bad idle...tried everything need help!!!

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04-23-2010, 10:31 PM

Colinjohns

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Location: Rockwall, TX

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Year: 2001

Model: Cherokee

Engine: 4.0

1990 XJ bad idle...tried everything need help!!!

Hey guys, I am posting this for my brother. He posted before but not much came in return..so i figured we could try again. When he starts it cold it is fine for a few minutes until it gets some heat then it will slowly lose idle...from good to nothing and eventually stall or sit at a little below 100ish. His throttle body also started whining around the same time...loud medium pitch noise. He replaced throttle body but to no avail noise still there. He has tried it all....

Quote:

Originally Posted by yohan4jeep

Hello, I have a 1990 Jeep Cherokee XJ RENIX. I have recently been having a very low idle after the engine warms up and its to the point where it will stall at lights and so fourth, At a cold start up it is not as bad around 500-600 RPM in Park/Neutral. Once warm though it begins the low idle issue. So far I have Replace
IAC
TPS- Which I set at the .8 volt as specified by jeep dealer
Tested MAP Sensor with meter it is working in correct way
Tested MAT Sensor/CTS Sensor it is working correctly
Replaced all Spark Plugs/ Wires
Replaced Vacuum Hoses/ Sprayed Throttle Body Cleaner to check for leaks found none
Also have cleaned the throttle body and I have a fresh oil change in her too.
Replaced O2 Sensor
Also Fairly New K&N Air Filter
Ran Sea foam through Vacuum lines to clean injectors.
04/22/10- Checked ECU it is not the problem I am starting to think fuel pump or fuel filter or pressure regulator...

He has now added to the list..new fuel filter and pump and assembly. What else is there...he is going to try the fuel pressure regualator tomorrow...HELP!!!! Also new egr valve and solenoid added as well!!!

Last edited by Colinjohns; 04-23-2010 at 10:55 PM. Reason: forgot something

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04-23-2010, 10:48 PM

ol"blue

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Year: 2004

Model: Grand Cherokee

Engine: 4.7L V8

I don't know anything about the Renix system, but this might be helpful. >-> http://web.archive.org/web/200803151...iagnostics.htm
Dan

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04-23-2010, 10:54 PM

Colinjohns

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Year: 2001

Model: Cherokee

Engine: 4.0

Thanks!

Quote:

Originally Posted by ol"blue

I don't know anything about the Renix system, but this might be helpful. >-> http://web.archive.org/web/200803151...iagnostics.htm
Dan

Thanks! We used that page and a few others for all of the checking so far...great link! I also forgot to add there is a new egr valve and solenoid added as well..appreciate the time and thought guys!

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