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Darrano · Jan 17, 2008, 12:57 AM

My daughter has bought an old 1988 inline 6 Jeep in very good condition overall. That being said it wants to over rev ( between 1000 and 1800 ) rpm at times. I bought a maual( not my first or last) and have been ruling out likely faulty culprits.
* TPS, MAP Sensor

I will probably take it in, as ,my manual suggests, after trying what I have.
Anybody seen this?

Thanks
Darren

CaptainRich · Jan 17, 2008, 06:54 AM

Begin by inspecting for vacuum leaks. Deteriorated vacuum hoses could be allowing unmetered are in.
The idle speed actuator/stepper motor could be sticking/binding partially open intermittently. Try spraying a quality carb cleaner into the throttle body while the engine is running and warm. Pay special attention to the opening that houses the actuator.

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Darrano · Jan 20, 2008, 06:23 PM

Thanks a ton. We are on the same page. I did take out that component and make sure everything was cleaned with a good carb cleaner. I know I can test it with a volt meter also.That is my next component to change out, and I have been telling myself it seems more like a vacuum leak partly, because if you push inside the throttle body that extra little bit by hand(finger tips inside throttle body) to close any air. The idle does come down ~400 or so rpms, i.e. the thought of a small vacuum leak somewhere... maybe a friction point type spot or crack . I haven't ruled out worn throttle body either, but seems very rare. I am typing this with a cast on so pardon the typos. Nice diagram.

Darren

Zomega · Jan 23, 2008, 09:01 PM

Hello Darrano - An obvious but often overlooked cause - make sure that the accelerator pedal is not being compromised by floor mats / rubber floor mats / carpeting / etc, thereby trapping it in a slight acceleration position.
This has caused over-revving issues in the past in vehicles of mine.

Best Regards
Zom

Originally Posted by Darrano

My daughter has bought an old 1988 inline 6 Jeep in very good condition overall. That being said it wants to over rev ( between 1000 and 1800 ) rpm at times. I bought a maual( not my first or last) and have been ruling out likely faulty culprits.
* TPS, MAP Sensor

I will probably take it in, as ,my manual suggests, after trying what I have.
Anybody seen this?

Thanks
Darren