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Q-Jet problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BlazinNewTrails, Oct 8, 2002.

  1. BlazinNewTrails

    BlazinNewTrails Registered Member

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    I see from reading other posts on here that the quadrajets are supposded to be pretty decent carbs for wheelin'...

    Ummmm... Mine, if I am parked on a steep uphill grade will start loading up. It will get to the point of dying in about a minute. This has not happened on the street, but most roads aren't that steep.

    The truck just passed emissions the day before I bought it.
    The owner said he leaned it out and retarded the timing to get it through. I think he richened it up to much afterwards. The tail pipes were black and sooty, so I adjusted the mixture screws by ear. One in particular was pretty rich.

    The carb idles great on the level, has no flat spots under acceleration, and the secondaries seem to open fine...

    Any suggestions?
     
  2. BlazinNewTrails

    BlazinNewTrails Registered Member

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    16 views and no ideas?
    C'mon guys.. I know a Q-jet tweaker is out there somewhere. /forums/images/graemlins/laugh.gif
     
  3. imiceman44

    imiceman44 1 ton status

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    Sorry I didn't look at this before.
    Well for off camber and steep hills, it's the float bowl level that you should work on.
    It's not very easy to access it you have to take the top of the carb off, the rebuild kit has all the instructions you need to do it plus the parts, and it's around $20.
    After I rebuilt mine to the specs, it drove fine even up a 20ft slimy 100% slope (45 degrees). It was real muddy and I had the engine full throttle for 20 seconds and I got up no problem, I also almost rolled over sideways still no stumble
    I have to aggree with the magazines, the Q-Jet is not appreciated but it's the best and it's what's available in any truck out there.
    IceMan
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Pretty much agree with iceman, (check float level) only thing I can add is that the mix screws are for idle mix, not cruising or anything else. If you want to adjust the carbs mix during cruise, WOT, etc., you do that with the primary rods/jets, and the secondary rods/hangars. There are some other tuning aspects, but pretty much idle mix tuning is through the screws, cruise mix is through the primary rods/jets, and WOT is through the secondaries.
     
  5. BlazinNewTrails

    BlazinNewTrails Registered Member

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    Thanks guys!
    I knew someone(or two) would come through. /forums/images/graemlins/smile.gif
    I'm guessing then that the float for the primary is the culprit then?
    That would explain the flooding and dying on uphill slopes if it was spilling into the intake.
    I don't know if it's the duals with no crossover pipe(my first set up like that) or a carb problem.
    When accelerating from a stop it sounds kinda "chuggy" until it gets up a bit in rpm (2500-3000).
    When in Park/Nuetral and free rev'd it doesn't do that.
    Idea's?
     
  6. imiceman44

    imiceman44 1 ton status

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    I forgot to mention the breather, it also spills into the carb when going up hill so usually you could put a small rubber hose extention to it.
    IceMan
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    QJ only has one float, centrally located, so you only have one to worry about : )

    You might check/play with timing, "chuggy" could be caused by too much timing, or bad distributor components. Mine was.
     

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