Fast Idle question`
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Mountain Pass
Joined: Dec 2003
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Fast Idle question`
I have a 92 AWD with a 4.0 litre engine and the problem is every once and awhile the van will idle faster than usual. It will do this when the engine is at normal operating temp. Sometimes stalls when cold. I have also noticed a decrease in fuel milage. This is not a daily driver and does sit for extended periods. Could this be O2 sensor or cold start sensor? Where else should I look?
Thanks
Thanks
Postmaster
Joined: Sep 2003
Posts: 4,452
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From: Southern California
For the 4.0L, it's right on top of the throttle body near the front of the engine, it's cylindrical with a 2-pin connector and is held by two bolts, you can't miss it. Remove it, clean it with throttle body cleaner, and also clean the passages with some small wire brushes.
It might be best, after removal, to separate the valve from the solenoid before cleaning.
It might be best, after removal, to separate the valve from the solenoid before cleaning.
Freshman User
Joined: Mar 2005
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Fast Idle
Check the vacuum lines on the manifold. Its located on the driver's side of the engine compartment toward the firewall. I had a hose off and my '92 4.0 idled at about 2500 RPM.
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Mountain Pass
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Good point, and in addition to that, the computer has a limited ability to diagnose its own IAC valve. So if there is a bad enough problem with it, then you could get a code for that. The chances of the computer detecting IAC problems is pretty slim, but it can sometimes.
Post Fiend
Joined: Oct 2005
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From: Kiev, Ukraine
As I remember, Aero '92 is OBDI. OBD-II lets you to see engine data, idle air flow (MAF) and IAC flow. Thats why we have to use mere primitive ways to find a sourse of the problem. I used to remove idle control solenoid (valve was leaved on thoutle body) and look at the result. It is possible to push the valve, and motor speeds up. But do not disconnect harnes from solenoid, or CE may appeare...