Why would gas be coming out of my exhaust pipe?

Discussion in 'Chevy Truck Forum' started by Richard G.III, Dec 26, 2017.

  1. Richard G.III

    Richard G.III New Member

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    Changed my injectors and manifold on my Vortec V-8 that had been vapor locking. Still won't start and there is gas coming out my exhaust pipe... Could anyone explain what I may have done or not done that would cause this and what I need to do to fix this problem.
     
  2. greencamaro1981

    greencamaro1981 Full Member

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    I wish I knew what we were working on but I bet the fuel regulator is stuck open and allowing fuel to blow through the injectors.
     
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  3. MikeG

    MikeG Full Member

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    A Cylinder not firing allowing raw fuel to just exit out the Exhaust Valve..............?


    Hopefully this is a worse case scenario :help:
     
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  4. Richard G.III

    Richard G.III New Member

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    Sorry about not giving more detailed info.. Its a 99 Tahoe Vortec V-8, I put it in my truck about 2 yes ago. The fuel regulator is brand new but the spider injector system was taken off of another motor from pull-a-part.
     
  5. dirtrider73068

    dirtrider73068 Senior Moderator
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    These spider injections were very prone to either stick shut best option or stick open and in some cases would gas hydro lock a motor. Most times its the poppits that would stick shut or open. These a bolt on swap upgrade spider injection kit that is better and makes a whole different motor.
     
  6. greencamaro1981

    greencamaro1981 Full Member

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  7. hatzie

    hatzie Full Member

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    #7 hatzie, Jan 5, 2018
    Last edited: Jan 5, 2018
    If she's blowing Gasoline out the exhaust it's also diluting the crankcase oil. You need to fix this ASAP or you'll permanently damage the engine.

    Usually it's the fuel pressure regulator, that you already replaced, or the spider hasn't been updated from CFI to the AC Delco 217-3029 or Delphi FJ10566 MPFI. The older CFI spiders are problem children now that they have some age on em. I would never trust a yard unit. The spider may be what put that rig in the yard.

    The updated MPFI injectors are less prone to clog up and they use electronic solenoids at the injectors rather than depending on fuel pressure from the main box to open the, easy to clog, poppet injectors.
    At $200-$250 for the AC Delco part and $400 for the Delphi part... they ain't cheap... but she'll run like a completely different rig for you.

    The Delphi is the true OEM part. The AC Delco is a reboxed unit. It might be the exact same part as one of the cheaper alternatives just in a Delco box. That being said. AC Delco is still OEM GM. Before they will re-box a part it has to be tested to meet certain specs.
    Be sure to replace the injector seals and lube em with Sil-Glyde.
     
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