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Hesitation

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Toad, Apr 16, 2000.

  1. Toad

    Toad 1/2 ton status

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    On my 76 350 4bl Quadrajet, I've rebuilt my carb, set the timming, spark plugs, new wires, new filter, fuel pump, HEI electronic module-flat banana shaped thing ( I need sleep I can't think right now), and who knows what else and my truck still hesitates when I stomp on the gas. Any Ideas on how to fix this?

    I noticed my metal fuel line going into the fuel filter is twisted a little. Could this be the problem? Do I need to rebuild the carb again? When hooked up to a vacume guage I get about 13 wich would indicate an intake leak but everything seems o.k.

    Oh yeah, (I hope your still reading this ridiculouly long post) I tried the vacume guage carb mixture adjustment and it didn't seem to help.

    Please help!!
     
  2. rich

    rich 1/2 ton status

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    If adjusting the mixture screws on the carb did not make a difference in the way the engine runs, then there's probably a vacuum leak somewhere.

    Also, advancing the timing over the stock setting will help compensate for carb problems and will give you more low RPM torque. But don't advance it too far or the engine will spark knock (rattling sound) which can eat pistons or other parts. And if you advance the timing too much it will also make the engine difficult to start. If you are messing around with the timing, advance it a little at a time and then test drive it to make sure it's not spark knocking.

    Richard
    '76 K-5 Blazer
    '90 K-5 Blazer
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    If that motor is any good you should be pulling 18 or better unless your running some monster cam. You have a leak somewhere. Try checking the heater controls for the leak. It maybe the leak is inside the truck. A quick easy check would be to put the hose off the T behind the carb and plug it and recheck the vac. Use some carb cleaner around the base of the cab to check for leaks there. The brake booster can also leak internaly try caping the line running to it and checking vac then. If you still don't find a leak then you may have a bad intake gasket.

    Diging it in the dirt with my K5's
    Grim-Reaper
     
  4. Toad

    Toad 1/2 ton status

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    Thanks guys. Grim I know you are the Quadrajet Jedi Master (kid's watching Star Wars in the background) so I will do anything you say. I'll let you know if I find the problem. Thanks
     

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