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question on backfiring lately

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Bross82, May 8, 2002.

  1. Bross82

    Bross82 1/2 ton status

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    hey, i read earlier posts before and i think i remember them saying that backfiring is usually related to timing... i just changed my timing chain 2 months ago, but it didnt start doing it until about a month later.... it mainly does it when i have just started driving and when i let off on the gas.... it seems like it cleans out after about 2 miles or so and then runs with mostly no backfires at all.

    also, i've been planning on changing my spark plugs again. could it be from if a few of the plugs were fowled, or if the 2 plugs might not be that good... i havent noticed lately... but before i could see slight flashes at night from 2 spark plugs on the driver side, the boots were on good and the plugs were in all the way too.... some people before just recommended getting better plugs than autolites.

    thanks,
    matt
     
  2. Sandman

    Sandman 3/4 ton status Author

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    maybe you have a stickey valve or lifter. How many miles are on it? Once it warms up some it might loosen back up.
     
  3. Bross82

    Bross82 1/2 ton status

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    well....on the truck there's 133000 mi... but the origional engine was swapped out because the previous owner went somewhere to get oil changes that didnt actually do an oil change.... so... this engine came out of an 85 pickup... anyways... i think it has close to the trucks miles on it, but i'm not really positive.

    i dont know if this could have an effect on this, but my valve covers leak a little oil. like i said i think its only a little... so everything should still be lubricated alright i think, unless it effects the pressure

    matt
     
  4. SkulzNBonz

    SkulzNBonz 1/2 ton status

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    Mine's doing something similar, the cause of which is a choke and carb in need of a rebuild.
     
  5. Bross82

    Bross82 1/2 ton status

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    i'll probably have to deal with it for now then... dont have the money for a rebuild or new carb.

    thanks,
    matt
     
  6. 74k5inVA

    74k5inVA 1/2 ton status

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    mine backfired too, until i fixed the exhaust leak from the exhaust manifold, there was no donut in it.
     
  7. MilpitasK5

    MilpitasK5 1/2 ton status

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    I have the same problem and I've been trying to save up for a Choke and Carb rebuild also. Fixed the exhuast manifold and also had the air fuel mixture adjusted. It helped but went back to normal after a few miles. I'm pretty it's the carb though.
    I wonder if it will smog the way it's runnin'. I'm due in October = (.
     
  8. RaisedK5

    RaisedK5 1/2 ton status

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    Guys, i just rebuilt my carb and replaced my divorced choke for 25 bucks, the rebuild kit was like 15 and the choke was 10, mine was backfireing a little, plus my timing was a bit off, but now all is right in the underhood world, so if i were y'all i'd tune up the carb clean up or replace the choke, and check the timing. my .02
     
  9. 73blazerUSMC

    73blazerUSMC Registered Member

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    Yea mine does that too i have headers and the flanges where the header collector meets my exaust system on bolth sides and warped so no matter how many times i replace the gasket its still does it i need to take them off and pound them back straight i would check your exaust first for it is the cheapest thing to fix call it wishful thinking
     

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