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TBI Idle Speed ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by hpfire7227, Nov 15, 2000.

  1. hpfire7227

    hpfire7227 Registered Member

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    Holland Patent, NY
    Greetings. Just wanted to throw this out and if anybody has any ideas or experience let me know...
    Just had a fuel injector replaced after a LONG LONG battle with the Blazer to get it running right. Thing is, now my idle speed is soaring and I fear I will blow my precious 5.7 L on one of these 30 degree 20W50 mornings. So fellas, I know that they say you can't touch FI idle speed because it's controlled by the ECM, but I say screw that, there MUST be something else. You guys know of anything?? Also, be advised that I have changed the O2 sensor, the throttle position sensor, the idle air control valve, the coolant temp. sensor, and a faulty vacuum line from the map sensor to the EGR. Despite all that, the idle still screams. So.....

    10 BOLTS O' FUN
     
  2. Bigd

    Bigd 1/2 ton status

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    Just a question, have you had the Computer checked?Are you getting any error codes?
     
  3. coopertwpk

    coopertwpk 1/2 ton status

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    Ok to adjust the IAC valve put in a jumper for code retrieval (top left plugs) turn on ignition go to passenger side of engine unplug IAC valve (rear four plug) ,now turn off ignition pull out jumper .now use an awl and remove plug out of the front of the throttle body rights side small round plug it has a #10 torx underneath it start motor and turn torx to adjust the idle speed once set turn off motor and plug in the IAC valve ,If this doesnt lower it enough your throttle position sensor may be bad or the throttle flaps may be out of center.
     
  4. hpfire7227

    hpfire7227 Registered Member

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    Nope, never had the computer checked. And OK, I'll try to adjust the IAC like you said. Thanks for the help.

    10 BOLTS O' FUN
     
  5. ken

    ken 1/2 ton status

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    I had the same problem...it turned out to be the $4 gasket between the TBI and intake manifold. Squirt some quick start around the base of the TBI while its running to see if the idle changes (meaning bad gasket).

    ken
     
  6. realsquash

    realsquash 1/2 ton status

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    Be more specific man! What *IS* the idle speed? If it runs at 1200 rpm when u start and slowly goes back down to 525 rpm then nothing is wrong. If it starts at 2000 and doesn't slow down, that is a problem. Does the check engine light come on?

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     

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