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new carb dieseling-solved!

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by K5Buckeye, Sep 15, 2001.

  1. K5Buckeye

    K5Buckeye Registered Member

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    Yahoo! Spent the day trying to figure this thing out. First, no vacuum from the carb. I blocked it off. Then, from the "T", I spliced that to the dist. Truck runs great. No more hesitation. Starts on the first crank. I love it! Can't take any of the credit though. My buddy is a mechanic and I finally gave in and called him at the shop. He told me what to try. Learn something new everyday.
    Question: Actually, the dieseling stopped a few days ago when I filled the tank with 89 vs. 87. Why?

    1972 K5
    1991 Jimmy
     
  2. Triaged

    Triaged 1/2 ton status

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    The 87 is easer to ignite than the 89. Check your plugs to see if they show signs of running hot. You may need to go down a heat range.

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  3. K5Buckeye

    K5Buckeye Registered Member

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    Triaged,
    I don't have many years of wrenching. What do you mean by "go down a heat range"? And what do I look for on the plugs?
    Thanks.
    Rodel

    1972 K5
    1991 Jimmy
     
  4. Triaged

    Triaged 1/2 ton status

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    Pull out the sparkplugs and put them into a numbered piece of cardboard with holes punched into it. Than look at the insulator (ceramic part around the center electrode) and electrodes. "The effects of high temp on a spark plug are indicated by clean white often blistered insulator. This can also be accompanied by excessive wear of the electrode, and the absence of deposits." This is a " from my Chilton's manual. In the manual are also color pic's of what it looks like. If all of your spark plugs look like this (and the timing is set correctly) than going to the lower "heat range" should solve your prob. The heat range is how fast the plug can give off heat. If yours are holding in too mugh heat they can get hot enough to ignite the A/F mixture before the spark happens (or when the spark stops when you shut off the truck). While you have the plugs out write down the part #. Than go to the parts store and have them look up the correct # for your truck. If you have to go down 1 heat range (the spark plug will give off heat faster the parts guy will have to look it up in the plug manufactures book).

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     

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