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Need some serious help!

Discussion in 'The Garage' started by Chubby, Nov 5, 2002.

  1. Chubby

    Chubby Registered Member

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    Location:
    Cleveland, Ohio
    I used my 77' 305/350TH/Np205 Jimmy to haul back a parts truck for a friend yesterday. Truck pulled great, except for the following puzzling issue:

    3 seperate times after I filled up with gas, I would head back out on the road and this problem would occur. I would start to climb a long grade on the Interstate and half way up the motor would start to miss. No drop in the gauges, no dim in the lights and as soon as I let off the gas the motor ran smooth. I would pull over, let it idle and then take the rpms' up to about 3K...no problem..off and driving again. Drove the Jimmy to work today, without out the trailer and it ran great, even up a grade!? Only failure I had was the pass side exhaust pipe came loose right by the down pipe, but not unattached.

    Any ideas?
     
  2. TopOff

    TopOff 1/2 ton status

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    Fuel vapor lock???

    Do you have catalytic converters? Plugged exhaust???

    Do you still have points? No you should have HEI on your '77 right? HEI module???

    /forums/images/graemlins/confused.gif

    Good luck.
     
  3. Chubby

    Chubby Registered Member

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    No cats, HEI, not sure about the vapor lock...truck wasn't running hot at all. I thought maybe fuel pump going bad, choke closing, or popping back through that loose exhaust pipe?
     
  4. 87sm465np208

    87sm465np208 1/2 ton status

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    yea id look at yur fuel pump, maybe that is the culprit, or maybe its the karburator, a setting on there might have to be changed, or the igntion advance thinggy?. anyhow, good luck with your truck, sounds bad ass /forums/images/graemlins/thumb.gif

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  5. chulisohombre

    chulisohombre 1/2 ton status

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    if you were heavy on the gas for a while going uphill maybe the carb was flooding the cylanders.i have this problem hauling sometimes.
     
  6. Blazer79

    Blazer79 1/2 ton status

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    Sounds like fuel vapor lock to me too. Used to happen to me and scared the /forums/images/graemlins/ignore.gif of me the first time it happened.
     
  7. GMslave

    GMslave 1/2 ton status

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    Check your timing and octane/quality vs your compression. You may have been detonating.
     
  8. Chubby

    Chubby Registered Member

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    It really felt like the motor was starved for gas...just not enough power! I have to think it is the fuel pump just not able to keep up under a big load...specially since it runs awsome with the load and at idle?!
     

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