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What is a misfire and what causes it?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fortcollinsram, Nov 14, 2001.

  1. fortcollinsram

    fortcollinsram 1/2 ton status

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    My friend just called my about the Blazer he is looking at and it has a few problems...
    1. He said it was misfiring...What excactly is this and how is it fixed?
    2. How hard is it to bleed brakes?

    If I have any more ?'s...trust me, this'll be the first place I come

    I am about to purchase (i.e. this week [​IMG], 11/15/2001)a 1987 K5. I am so excited. I has a 4" lift, 33's, Flowmaster, & pretty to boot
     
  2. meatloafK5

    meatloafK5 Registered Member

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    Misfires usually occur due to your timing being off. Check your Chilton book, they explain it in a simple way, and tell you how to fix it.

    "stupid people are simply alive because it's illegal to kill them..."

    84 K5 Blazer 305(for now) many mods coming....including a 350
     
  3. Twiz

    Twiz 1/2 ton status

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    "What is a missfire, how do you fix it?"
    - Anything that quenches or prevents the Air/Fuel mixture from igniting or burning completly
    - This condition "feels" like a bad shake or vibration from the engine, related to engine R.P.M.
    - Several posible causes that need to be diagnosed properly. Most comonly: Bad/shorting spark plug wires, cracked or carbon traced Dis. cap and roter, cracked worn or fouled spark plugs. Also, can be mechanicly (compression/valves ect.) or fuel related.
    As you can see, there are meny possible ressons for a engine missfire. A better discription of exactly what is happening may help narrow down the possibilits.

    "How hard is it to bleed brakes?"
    - Not very hard at all, as long as it is done properly. Start by finding out why you nee to bleed them. (What happend? What was replaced?)
    Make sure the master cyl is full and remains full threout the bleed procedure. ake sure the cap is reinstalled after filling. Start with the RR, than LR, than RF, than LF. (work from the brakes that are furthes away from he master cyl, and work you wy closer.) Becarefull "craking" open the bleed screws, sometimes they can be rusted in place. Also, some brakeing sys. have a combination valve that may default and close off the line. There are clips that can be used o hold the combination valve in the "open" postion.


    <font color=blue>Twiz</font color=blue>
     
  4. jimmyjack

    jimmyjack 1/2 ton status

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    Any problems that I've ever had with a misfire has always (ALWAYS) been because of a vacuum problem. Check all the hoses and tubes around the carb and manifold area. The extra air being sucked in will wreck havoc with the air/fuel mixture. While the engine is running spray some carb cleaner around the base of the carb and the manifold. If you have a leak the cleaner will displace any oxygen and the revs will increase for a second or two, just be careful spraying it around the distributor!!!! Big ball of fire will happen!

    That jeep thing? Yah I understand it....... Like my Blazer? <a target="_blank" href=http://community.webshots.com/user/blazerk5>http://community.webshots.com/user/blazerk5</a>
    Jim
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    A single cylinder misfire is not a vacuum leak. An engine with a vacuum leak runs crappy because it's too lean and has a hard time igniting the fuel mixture, but that doesn't cause a dead miss. Basically that just makes all of the cylinders miss fire.

    If we're only talking about one cylinder, it's cause by lack of compression, fuel, or spark to one cylinder. Fuel is most likely not the cause.

    Check your whole ignition system after the coil and do a compression test and you'll be well on your way to finding your misfire condition.

    As for bleeding brakes it's a piece of cake.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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