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87 K5 running lean?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 87BrnRsd, Sep 16, 2004.

  1. 87BrnRsd

    87BrnRsd 1/2 ton status

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    I have a 1987 K5 with a rebuilt 350, and tbi. Pretty much everything on the engine is stock. The truck is running pretty lean and I am wondering how to fix this. Sorry I havent given any more info, but I will pull the codes tomorrow to see if you guys can diagnose them. Thanks.
    -Harrison
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    What makes you think it is running lean?
     
  3. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    vaccuum leak?
     
  4. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Unburned gas in the tip of the exhaust pipe.
    -Harrison
     
  5. js4x4

    js4x4 1/2 ton status

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    unburned..?? I get H2O form/drip from my exhaust when shes tuned right...i'd think if you had unburned gas (rich?) and if ya have THAT much am surprised it runs...
     
  6. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Its not THAT much. It doesnt drip. If you put your finger in the tip of the exhaust and pull it out, its moist and smells like gas. Its throwing a code, so I am getting ready to go check it now. Will let you know what it says.
    -Harrison
     
  7. dheavychevy38

    dheavychevy38 1/2 ton status Premium Member

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    the base gasket on for the tbi is common for leaking check for the o'2 sensor also
     
  8. bablazer73

    bablazer73 1/2 ton status

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    I just went through something similar with the wifes truck. Was running lean, but the computer would dump fuel to try and comensate for it. The vacuum ports for the MAP sensor and PCV were plugged with carbon. the MAP wasn't getting a true reading. Cleaned them out and runs great now.
     
  9. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Thanks! I did that and it runs good now. Problem fixed.
    -Harrison
     
  10. opfor2

    opfor2 1/2 ton status

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    Where is the MAP sensor on a 90 Blazer ?
     
  11. bablazer73

    bablazer73 1/2 ton status

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    Right side of intake manifold, It's attached to a bracket thats just to the side of the Throttle body.
     
  12. opfor2

    opfor2 1/2 ton status

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    Thanks, I'll have to clean it..

    Dan...
     

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