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TBI idling very high

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mrkay, May 17, 2000.

  1. mrkay

    mrkay Registered Member

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    Hi Gang...I have an 88 Blazer Silverado 350/auto with TBI. The truck idles very high when warmed up, and idles unevenly when warming up. Is this something that can be adjusted mechanically or is it somekind of computer/emission thing? Could it be just a gummed up linkage?
    Your advose is greatly appreciated.

    mtkay


    Old Plymouth Rocker
     
  2. Truckfan2

    Truckfan2 1/2 ton status

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    check the air cleaner!!! actually my truck idles high when warming up and it doesn't take off when punched. Only does it start acting normal when it's warm.

    NEVER been stuck... *yet*
     
  3. 88Jimmy

    88Jimmy 1/2 ton status

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    Replace the gasket under the TBI carb

    350 Vortec TPI D60 14Bolt 4.56 4"lift 35 BFG A/T
     
  4. bablazer73

    bablazer73 1/2 ton status

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    I would also remove the idle control selonoid and clean it. the selonoid is in a passage that gets built up with carbon and won't alow it to operate smoothly. clean it completly including the shaft inside the spring.

    your right. I don't understand the jeep thing!
     
  5. GUMBY

    GUMBY Registered Member

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    I would check the gasket under the throttle body by spraying carb cleaner or wd-40 around the gasket while the engine is running. If the idle goes up, the gasket has a leak. Also, I had a similar problem with the idle going up and down while warming up and it was the EGR unit. Have someone check it.
     
  6. 89Jimmy

    89Jimmy 1/2 ton status

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    You could also try spraying carb cleaner on the intake gasket. If there is a vacumn leak there, the rpms will jump when the cleaner hits it.

    John

    So Much to do, So LITTLE cash.
     
  7. Dieselmh

    Dieselmh 1/2 ton status

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    If your clean air intake tube has the flapper in it to control air volume, check to make sure it isn't gummed up. Pull the tube off and make sure the flapper moves freely, if not, clean it good. Just my two cents.

    Diesel

    If it ain't broke, fix it 'til it is.[​IMG]
     
  8. mrkay

    mrkay Registered Member

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    This is great!
    I did'nt pass the nox emmission test for my sticker, so I went to a shop to have them check out the emission gadgets. They found a vacuum hose routed wrong from (or to) the EGR unit and it tested 1.0 for nox after fixing. It does'nt run any better, though. I think someone may have re-routed the vacuum to smooth out the engine.
    This emission stuff is a real mystery to me. Anyway nothing they did changed the high idle after warm-up or uneven idle during warm-up. Sooooooo, I turned to the best brotherhood I could find. I will check out the things you suggested and let you know how it comes out. I'll look into my trusty Hayes book and find out where all these things are and start tweaking.

    Thanks, again....

    Rock climbing on Plymouth Rock
    with my 88 Blazer 350/Auto/TBI
     
  9. River

    River 1/2 ton status

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    Check the coolant temperture sender, when the sender is fault it wil give a wrong value to the computer. The computer thinks the engine is cold. This happend to me one day after 2 day`s i found out it was the coolant sensor it`s located in the intake manifold just behind the thermostat.

    greetings from Amsterdam,

    River
     

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