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I know some of you guys posess Chevy 350 genius... please help me out!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ArrowheadK5, Apr 23, 2003.

  1. ArrowheadK5

    ArrowheadK5 1/2 ton status

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    It's been a while since I have been in the forums. School sucks.
    /forums/images/graemlins/frown.gif
    I need help with my truck. It's an 87 K20 with a standard 350 TBI (with a hellish 210K miles). And, very simply, when it's cold and rainy, it won't start.
    The plugs, plug wires, distributor cap and rotor are all new with no progress being achieved with thier replacement. The only reliable fix is to wait for it to get sunny out and BAM it start instantly. Oftentimes after an 'episode' it will run roughly for a short while, as if it were flooded.
    I will gladly provide any other information needed to help diagnose this problem. Thanks for reading my post and for any help you might have.

    P.S., my truck looks almost EXACTLY like this: /forums/images/graemlins/truck.gif
     
  2. DUKE

    DUKE 1/2 ton status

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    if water gets anywhere near the carb, it will not run. thats an exageration, but water in there is bad, even a little bit will make it stumble and stall. I was working on mine with the hood up, went inside to pee and it rained just had to wait for her to dry out. If there is anyway for the rain to get under the hood that could be whats up.
     
  3. Poohbair

    Poohbair 1/2 ton status

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    ...just a guess here, but maybe water in the gas tank?? On cold days causes condensation to form, therefor water in gas/lines?
    Or maybe I have my head up my ass?
     
  4. ds350

    ds350 1/2 ton status

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    Have you checked your fuel system? TBI filters are know to clog fairly quickly and the pump may not be working properly. When it is not running, the first things to check are fuel and spark.

    Good luck, and let us know what you find.
     
  5. Blue85

    Blue85 Troll Premium Member

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    I agree with checking the fuel filter.

    Does the fuel pump prime? If not, it will take a long time cranking for the engine to start, since it has to crank until you get some oil pressure before the fuel pump turns on. Then having cold weather would thicken the oil up and this process might take so long that it seems to never happen. You can usually hear the pump prime by turning the key to "ON" without turning it to "START". It should buzz for a couple seconds.

    Does it fire at all when it's cold?
     
  6. Blazer1970

    Blazer1970 1/2 ton status

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    It has to be an electrical problem. Maybe replace the coil. Have someone crank it in the dark (while it is wet) while you look under the hood and see if you can see where your spark is grounding out.
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Cheap things to try:
    Replace fuel filter: Because you should (assuming it hasn't been changed in a while)
    Add drygas to tank: Remove moisture
    On a warm dry day and engine cool, soak the [censored] out of the wires, coil, distributor, etc with silicone spray (it will repel water).

    It could also be a bad sensor/wire that's affected by moisture, but to not start at all, seems a little weird for that.
     
  8. ArrowheadK5

    ArrowheadK5 1/2 ton status

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    Thanks for all the replies! I had forgotten about how active this community is.
    I will look into replacing the fuel pump. Any tips about doing it on a dual-tank system when I only use one tank (right)? BTW, I do hear the pump priming itself when the key is on.
    And as for the coldness, It only has a problem when it is really wet and somewhat cold. In fact, I haven't tried it when it's warm and wet.
    I mean, this winter it was less than -20 degrees out some mornings. That will freeze the human body solid in like ten minutes, but my truck started every time without a block heater. But as soon as we had a rainy spring day, bam, it wouldn't start.
    Thanks again!
    /forums/images/graemlins/truck.gif
     
  9. 90K5

    90K5 1/2 ton status

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    look on the underside of the hood. there should be a strip of rubber that runs along the cowl, when the hood is closed, it keeps water out. if it is rotten or not there, it doesnt keep water out and it pours all over the distributor cap...mine was missing for a while and i had the same problems...good luck.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    So if the fuel pump/pickup are submerged in fuel (such as a full tank) why would cold or wet weather matter, and why would you replace it based on that info?

    I'm not saying it CAN'T be the fuel pump, but come on, how is water related to an electric fuel pump, especially when the problem only happens when it's wet out? Water floats on the surface of gas, the pickup is at the bottom of the tank, and the "sock" filter at the bottom of the pickup prevents water from passing through.
     

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