Problem with 88 gmc 1 ton

Discussion in 'GMC Truck Forum' started by jrsrcvry, Oct 19, 2005.

  1. jrsrcvry

    jrsrcvry Member

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    I have bought this truck from California and rebuilt the top end on the way home with it. Now i am having a problem with a sensor and i have replaced all of them and still the truck is sucking air way bad. I am wondering it is a TBI and wanted to see if I can Just change the intake and distrutor and make it work or if the heads are series 2 that year or not.
     
  2. 72'CaminoKid

    72'CaminoKid Senior Member

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    give us some more info on the problem if possible.....
     
  3. jrsrcvry

    jrsrcvry Member

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    Well it sounds like a vacuum leak. And it runs like a vac. leak. I got a tip that it might be the gasket under the throttle body is cracked or has pulled into the intake. The throttle body is just sucking a massive amount of air.
     
  4. jrsrcvry

    jrsrcvry Member

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    There are alot of wires that are cut or spliced under the hood. I mean i am good with older car and vaccum with HEI and carburated but not the new stuff and the whole electrical stuff.
     
  5. chevyguy

    chevyguy Senior Member

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    It is easy to convert to carb and hei with these older models. The hardest part is a fuel pressure regulator to drop fuel pressure from around 12-13 to around 8 psi. Other than that it is simply finding a 12 volt power supply for the ignition system that works off the switch. No biggie, but i agree it sounds like a vacuum leak. Did you use the gaskets, or RTV at the front and back of the intake manifold? The gaskets are junk and almost always leak.
     
  6. jrsrcvry

    jrsrcvry Member

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    I did not replace it I had it done at a shop. And the guy builds race cars so i would hope that he knows what he was doing but i think that is something i am going to call him and ask. Well i am going to go work on this thing. If there are any more suggestions i would appreciate it.
     
  7. chevyguy

    chevyguy Senior Member

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    The pro that built the motor does not eliminate it, I am sure you know that, but accidents can happen and Unless I miss my guess, I suspect a vacuum leak at the front or rear of the intake. You can find out with a can of wd 40. Simple.
     

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