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7 plugs white, 1 plug black and sutty.....

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by foxman, Aug 21, 2002.

  1. foxman

    foxman 1/2 ton status

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    I wish I could show you guys a picture of this plug. It is the #1 cylinder plug and it is the only dirty one out of all of them. About every 1000 miles a "bridge" of carbon like material forms across the spark plug gap giving me a dead cylinder. It seems to run a little rough even with a new plug in it, yet I can't seem to narrow the problem down. Here's the story... New cap/Rotor, new wires, new plugs. This is all since the problem has happened, and it still seems to happen. The engine has @ 180,000 miles on it, and no major problems yet...
    any Ideas??? Thanks...
     
  2. Sandman

    Sandman 3/4 ton status Author

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    My old 400 did this after many many miles. Mine was oil. Either the rings were passing it or the valve guides were. I had to pull and clean my number 7 about every 500 miles. Might be time to start saving up for a rebuild.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Mines the same way, 1 plug (#6?) tends to be fouled when I check them, but I KNOW mines oil, because the engine is worn out...about 3000RPM under load, she starts blowing smoke. Of course the leaking valve seals don't help either, but thats typical lol.
     
  4. alec78

    alec78 1/2 ton status

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    Same problem on my old 74 C10 (stop laughing at least it was a truck). Bad rings were my culpret. I guess I was lucky. It was every 400 miles on ALL cylinders. A compression check will tell you. You'll find cylinder 1 to be lower than others. If it is a lot lower its the valves. A little is the rings.
     
  5. OLDSTEEL

    OLDSTEEL 1/2 ton status

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    Sure sounds like you need to rebuild but, in the mean time you could use a plug cup it will help with the build up and you won't need to clean it as offten.
     
  6. 76chevy

    76chevy 1/2 ton status

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    Aren't they ALL supposed to be black? /forums/images/icons/grin.gif
     
  7. 70~K5

    70~K5 1/2 ton status

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    A freind of mine had this problem and didn't have the money to fix it. So we put new plugs in it and saved the 7 good ones. When the one plug would foul we'd put one of the old good ones in it. By the time he used all 7 it was time for a new set.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    If they are just carbon fouled, cleaning them off with a brush or knife point will bring them back to like new. My one bad plug I have no problem scraping the carbon off of it, and it runs fine while its clean : )
     

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