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Backfire after 4.10's

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 76_Cheyenne, Sep 1, 2002.

  1. 76_Cheyenne

    76_Cheyenne 1/2 ton status

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    Backfire after 4.10\'s

    I just got my new 4.10s in my K10 with 35"s. when I let off the gas fast, or when going down a hill and let off the gas I get some backfiring and poping. Is this because the engine now has a lot more compression rolling down the hill's and is normal or does this mean that my timing is off? Thanks
     
  2. 95 Silverado

    95 Silverado 1/2 ton status

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    Re: Backfire after 4.10\'s

    it's probably more noticable now that the engine is turning at a higher rpm, it is probably due to the timing setting. Resetting the timing should quiet it down.
     
  3. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    Re: Backfire after 4.10\'s

    You also might lean out the carb mixture just a little as well as check the timing.
    Bill
     
  4. 83PJW

    83PJW 1/2 ton status

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    Re: Backfire after 4.10\'s

    also vacum leaks check it out.
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Re: Backfire after 4.10\'s

    Maybe its time to pack the muffler bearings /forums/images/icons/smirk.gif
     
  6. 76_Cheyenne

    76_Cheyenne 1/2 ton status

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    Re: Backfire after 4.10\'s

    haha... i bet if I had mufflers instead of glasspacks it wouldn't be as bad.
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Backfire after 4.10\'s

    Well thats where the popping comes from then.
     
  8. NoSmog73

    NoSmog73 1/2 ton status

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    Re: Backfire after 4.10\'s

    More often then not it will be an exhaust leak..Like mine was/is he he...mike /forums/images/icons/smile.gif
     
  9. 76_Cheyenne

    76_Cheyenne 1/2 ton status

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    Re: Backfire after 4.10\'s

    But if it was an exhaust leak wouldn't it be poping/backfiring all the time, this only occurs when the compression is built up in the cylinders and the revs are up.
     
  10. NoSmog73

    NoSmog73 1/2 ton status

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    Re: Backfire after 4.10\'s

    I was told by a member on here that I know,That it would be an exhaust leak like a crack in the manifold??? - (here is my situation,I have it in 2nd and floor it or get the rpm's up and let off the gas like,like coming to a stop and I get the popping through the pipes..) if it is different I too would like to find out why...Not meaning to hi-jack the post....mike /forums/images/icons/smile.gif /forums/images/icons/smile.gif /forums/images/icons/smile.gif
     
  11. 76_Cheyenne

    76_Cheyenne 1/2 ton status

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    Re: Backfire after 4.10\'s

    I put new headers and straight exhaust on a few months ago, and I checked and didnt see any leaks? It sorta sounds like a harley coming to a stop, all rumbly with an occasional backfire.
     
  12. ntaj*ep

    ntaj*ep 1/2 ton status

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    Re: Backfire after 4.10\'s

    Your using more compression braking, than before. If you have an adjustible vac. advance. You need to adjust it. Otherwise you just need to adjust your air/fuel mixture and timing. Or upshift and use the brakes. /forums/images/icons/grin.gif /forums/images/icons/tongue.gif
     
  13. 4x4Freak

    4x4Freak 1/2 ton status

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    Re: Backfire after 4.10\'s

    It's probably because the engine isnt running just right. If its not firing like it's supposed to it wont burn all the fuel and when that fuel hits the hot exhaust it ignites and backfires. My K30 did this for a while but it stopped after I replaced the plugs, wires, cap and rotor. It still does it ocassionally but not very often.

    Only reason I can think of for an exhaust leak to have an effect is if it's letting more oxygen in to let it ignite.
     

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