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88 TBI k5 backfiring?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Chaz88K5, Sep 16, 2001.

  1. Chaz88K5

    Chaz88K5 1/2 ton status

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    Ok well yesterday i took off from my street and got about 1/4 mile down the hwy and my truck backfired...this is about the 3rd or 4 time it has done this this month....i dont have a clue whats goin on...it dosent seem to be loosing any power...it actully feels like it got more.
    what i have is a 1988 K5 with TBI fuel injection, 700r4 tranny.. anyone have any answers for me?
    Chaz

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  2. TXsizeK5

    TXsizeK5 1/2 ton status

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    what do you mean by back fire?

    6in 87' K5 w/ 35" BFG muds.
    Kn filter

    What I need: 4.11 gears, Lim Slip Dif, Force2 Catback, rear springs , Throtle body spacer.
     
  3. Chaz88K5

    Chaz88K5 1/2 ton status

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    i dont know how else to explane it...it sounded like a shot gun goin off comin out my tail pipe!

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  4. Chaz88K5

    Chaz88K5 1/2 ton status

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    top

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  5. DMK

    DMK 1/2 ton status

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    Did check engine light come on? My 87 did this about 2 weeks ago while idleling. Light came on and disconnected battery after that it was fine. Had an 89 do it while driving, found the distributor hold down lose. It would let the distributor move. Also may need new ignition module. Check for codes if light is on.
     
  6. Chaz88K5

    Chaz88K5 1/2 ton status

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    the light dident come on for awhile after it happened...maybe 3 or 4 miles down the road....
    Chaz

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  7. Burt4x4

    Burt4x4 3/4 ton status

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    I don't know if this is the same, I'm carburated, but I had gotten some 'bad' gas and my rig started back firing too.
    Put some 92 in from one of the major players and no more POW down the road! Get a bottle of that injector cleaner and fill up with Chevron or Shell 92.... worth a shot??!!

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <a target="_blank" href=http://www.geocities.com/baja/5099>www.geocities.com/baja/5099</a>
     
  8. K5Jimmy

    K5Jimmy 1/2 ton status

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    Check your spark plug wires....especially if it does it primarily when you are on the gas....if you have duals, you may even notice a "beat" coming out of one side......stand on the brakes, and load the motor a bit, it may make a small problem more noticeable....

    Stuck?...Hell no..I still got some gas left..
     
  9. Panther

    Panther 1/2 ton status

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    What should we look for on the wires? Arcing, bad connections, all of the above. Does back-firing signify a non-firing cylinder?

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  10. jarheadk5

    jarheadk5 1/2 ton status

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    To look for arcing plug wires, pop the hood and start the engine, at night, in the DARK, and lightly spray some water from an old Windex bottle or something similar. Look for little sparks. This'll let you know if you've got any arcing wires, and if you look carefully, you might be able to isolate the bad wire. But in my opinion, if you've got arcing wires you should replace the whole set.


    September 11, 2001--"A date which will live in infamy"
     
  11. Chaz88K5

    Chaz88K5 1/2 ton status

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    Whoo hoo fixed the problem...you will never guss what it was...everything that happens to this truck is never what i think is wrong with it...like this time i was because my speedo quit working because a gear in the transfer case strped out...well fixed that and no more check engine light and no more back firing....last time i thought it was my tranny goin out...it felt like it was slipin like crazy....but nope...it was my fuel filter!!! i dont get it!

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  12. Panther

    Panther 1/2 ton status

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    I know how to find arcing wires (which I should do so I can rule that out [​IMG]).

    But my real question is...will a mis-firing cylinder (bad wire or whatever) cause backfiring up into the TB?

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  13. BobK

    BobK 1/2 ton status

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    Backfire out the tail pipe is caused by unburnt fuel in the exhaust system igniting.You gotta figure why there is unburnt fuel in the exhaust.A bad wire or plug could cause this.If the back fire was out the carb or TBI that's usually a timing issue.I'd check for a loose distributor and check your timing as well.
    I literally blew-up my exhaust when my HEI coil went on the fritz.Dumped a whole mess of gas into the exhaust and then all of a sudden it sounded like some-one was fireing a M-16 out the rear of the truck.Both my mufflers were blown apart at the seams.My wife was behind me in her Je@p and all she saw were flames!

    <font color=green>BobK<font color=green>
     
  14. Chaz88K5

    Chaz88K5 1/2 ton status

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    my cat is toast now....i dont think there is anything in it at all now (no biggie there)...i am not goin to worry about that untill i have to smog it...it sounds better with it toasted anyway.

    [​IMG]<font color=blue>Donations accepted for the "Build Chaz's 1972 K5 fund"!!!</font color=blue> [​IMG]
     
  15. Panther

    Panther 1/2 ton status

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    Thanks much Bob. That's the info I was looking for. I think it's actually backfiring out of the exhaust since I can smell the gas coming out when it runs. Gotta find the culprit cylinder. Thanks again!!

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     

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