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TBI hesitates when cold

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rick87K5, Sep 25, 2001.

  1. rick87K5

    rick87K5 Registered Member

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    Location:
    Austin, TX
    Hello all,
    My truck runs rough and hesitates upon first start in the morning. The idle will fluctuate sometimes also. I don't think that it's running rich; no dark or rich smelling exhaust. Once it gets going, it runs fine though. I don't think it reaches 130 degrees (beginning of closed loop mode?) before the hesitation quits. I've changed the coolant temperature sensor, but it didn't help the problem. Is this just a symptom associated with high-mileage engines (205K)? Any help or ideas anyone may have here would be greatly appreciated. Thanks.

    rick
     
  2. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Is that the sensor on top the manifold? Do you have that tube off the manifold to the intake. It heats the air so the TB isn't sucking in super cold air. It only messes things up when its reallycold air so that probably isnt it but I thought I'd open my mouth for the heck of it.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  3. rick87K5

    rick87K5 Registered Member

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    Blazer Boy,
    Yep, that's the sensor that threads into the top of the intake manifold, right next to the thermosthat housing. The tube from the exhaust manifold is on, although not perfectly. But, I agree with you, I don't think that's enough to cause the problem - it doesn't get that cold here (Austin, Texas). I appreciate the suggestion though - Thanks.

    rick
     
  4. GUMBY

    GUMBY Registered Member

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    It sounds like the EGR valve. It has a diaphram in it that can go bad and will cause your idle to fluctuate when the engine is trying to warm up. I had this problem and had it replaced. Have somebody check it.
     
  5. rick87K5

    rick87K5 Registered Member

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    Thanks Gumby,
    I'll have to check that out. Actually, the EGR valve that is in there is a cheapo Autozone version which can't be checked with a vacuum pump and the diaphragm movement can't be checked with your fingers either. I figure it may be in my best interest to change it; I've suspected it's not working right anyway.

    rick
     

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