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Q-jet problems

Discussion in 'The Garage' started by TWISTEDJACK, Jul 14, 2003.

  1. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    I took my truck out this weekend for a test run on the new motor. I just rebuilt this carb and it is new to this truck.
    It runs fine on the street but when I take it off road on any road that isn't smooth or is a little up hill it loads up terrible. I know the float level isn't too high. I have a Holley blue pump regulated down to 5 psi. I don't know where to start. /forums/images/graemlins/1zhelp.gif
     
  2. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    Come on guys, I know someone can help. I have to have it running by Friday because I am the trail boss on our club run this month. If I can't figure it out I am going to buy the 770 truck avenger. I sure miss fuel injection.
     
  3. Don

    Don 1/2 ton status

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    Did You?
    1. install the plastic baffle around the needle/seat?
    2. Set float level to the proper level?
    3. Fuel pressure is too low, bump up to 7-8lbs.
     
  4. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    [ QUOTE ]
    Did You?
    1. install the plastic baffle around the needle/seat? <font color="blue"> yes </font>
    2. Set float level to the proper level? <font color="blue"> yes </font>
    3. Fuel pressure is too low, bump up to 7-8lbs. <font color="blue"> makes the problem worse </font>

    [/ QUOTE ]
    I had my father look it over, he has rebuilt these carbs several times when he was a line mechanic for gm. He thought the high volume pump was causing the problem. /forums/images/graemlins/confused.gif
     
  5. redk5

    redk5 Registered Member

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    I agree with your father, I've rebuilt quite a few q-jets, if you have too much fuel going into the carb you will get problems like you describe, go to napa and buy a 15 dollar pump, see if helps, if it doesn't you have a spare trail part, other points, are you sure the regulator is working properly, let me know.
     
  6. florida4x4

    florida4x4 1/2 ton status

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    I have not put it into practice yet so I can't say from experience but I have been told that the optimum fuel pressure for a qjet is 4.5-6 lbs when using the .130 needle and seat.
     
  7. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    Tonight I am going back to the stock pump. It is kind of hard to know where to start when I change so many parts at once.
    New Motor (391 stroker)
    New elec. fuel pump
    New Carb (Projection before)
    New MSD ignition

    I am going to start with the fuel pump. See what we find later tonight.
     
  8. TONYP

    TONYP 1/2 ton status

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    I can get the "Jet Performance Stage 2" Q-Jet for $150.00, let me know /forums/images/graemlins/thumb.gif
     
  9. COCHEV

    COCHEV 1/2 ton status

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    is the float itself damaged, cracked?
     
  10. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    [ QUOTE ]
    I can get the "Jet Performance Stage 2" Q-Jet for $150.00, let me know /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    Son of a &amp;%^&amp;%*^% I just got sick of this thing. Everything has been checked and with the stock pump it is still acting funny. I just ordered a truck avenger 770.
    I hope it works out better than this one did. If not I will be getting a hold of you.
     

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