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Thread: High Idle In Neutral

  1. #1
    Garrett booster
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    Oct 2014
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    Illinois
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    High Idle In Neutral

    Need help with my car. My 1987 LeBaron daily driver has been undriveable with a high idle issue.

    The car has a 2.2L TI Engine. When in neutral the car idles at 2100 rpm. If the speedometer is above 0 mph the car idles high at 3000-3400 rpm.

    At the same time, if I set the cruise control at any speed, the car slowly increases its speed 1 mph at a time.

    If anyone has experienced this or is familiar with the issue, any help is appreciated.

    Thank you!

  2. #2
    Supporting Member II Turbo Mopar Contributor ajakeski's Avatar
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    Re: High Idle In Neutral

    Sounds like a vacuum leak. If one of the vacuum hoses has fallen offor is broken, that will allow unmetered air into the engine, causing high idle.
    Unmetered air refers to any air that enters the engine at a point other than the throttle opening.
    Check the vacuum hoses that go from the base of the throttle body down to the turbo inlet.

  3. #3
    Supporting Member II Turbo Mopar Contributor
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    Re: High Idle In Neutral

    Quote Originally Posted by ajakeski View Post
    Sounds like a vacuum leak. If one of the vacuum hoses has fallen offor is broken, that will allow unmetered air into the engine, causing high idle.
    Unmetered air refers to any air that enters the engine at a point other than the throttle opening.
    Check the vacuum hoses that go from the base of the throttle body down to the turbo inlet.
    My DD is an 87 log T1 and yes I have had the high idle from vacuum leaks. That is the first thing I check.
    The second item is a dirty AIS, I find I need to clean the AIS approx every 7K miles
    Here is my procedure.http://www.turbo-mopar.com/forums/sh...7-and-older-T1
    Regards,
    Miles

    DD '87 Sundance T1, 12PSI, SLH with rear disks
    '87 CSX #432

  4. #4
    Garrett booster
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    Re: High Idle In Neutral

    Goddam it this is why I love this community, thanks for the input guys.

    Visual inspection of the vacuum lines gave me nothing. They look intact, no cracks no tears.

    One more item to mention is that prior to the high idle, there was a period of time where the car would idle at 500 rpm. Car only died once but for the most part it would somehow stay alive at 500 rpm.

    That guide to refurbish the IAS is great, I'm gonna have to give it a go. I had luck fixing the power window motor and the headlight motor, both times found horrible plastic gears inside.

    I'll update as soon as I get a chance to take apart the IAS motor.

  5. #5
    Supporting Member II Turbo Mopar Contributor Dr. Johny Dodge's Avatar
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    Re: High Idle In Neutral

    the two short hoses connecting the throttle body to turbo and turbo to manifold
    ..
    check for splits of course but also see if you can move them - they might be loose

    over time they get soaked with oil & with repeated heat cycles and boost , I've blown the hose to the manifold off at one before .. more than once

    thing is , "off" doesn't necessary LOOK like off but sometimes is just a gap at an edge of the hose

  6. #6
    Garrett booster
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    Re: High Idle In Neutral

    I did go investigating today and the hose in worst condition was the line from the waste gate to the manifold (though I have a small "boost controller" as a bypass there). The hose coming from the waste gate was in pretty rough shape so I'm gonna start the replacement there. Does anyone know if the size of the vacuum nipple of the waste gate is slightly bigger? Couldn't get the hose to fit but then again i couldn't see exactly what I was doing. Any input is appreciated.

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