Q-Jet problems

Discussion in 'The Bench' started by 71_electra225, Nov 22, 2003.

  1. 71_electra225

    71_electra225 GM > Ford

    Finally getting to take my electra out a little today, i found out that the carb needs a *little* tuning. aside from the rough idle, the biggest concern that i have is when i floor the beast, it dies! any suggestions?
     
  2. Dan Healey

    Dan Healey Well-Known Member

    Does the accel pump squirt gas?

    Also you can check to make sure the choke isn't closing. Then again, it doesn't have to be the carb causing the problems (distributor, etc). You need to start eliminating things....
     
  3. bgs455

    bgs455 OIF OEF HOA ONE

    Also check you're fuel pump. It may be going bad and pumping just enough too keep it running at low speeds.
     
  4. IDOXLR8

    IDOXLR8 Senior Member

    Carburetor Problems

    Aastion, many things can cause this. You need to first check the the basics first like good ignition wires, points,vacuum leaks general engine condition.Check the dwell and make sure its at 30 degrees (.019 point gap) and the timing is set correctly. With that out of the way we get to the carburetor. First float level is very important. On other carburetor problems the main things that cause the condition you discriped would be choke pull offs yes there is most of the time more then one and are very important in the engines performance like creating a rich condition on start up and not letting the secondaries open untill warmed up and dampening them when they do open and could causes a lean condition. Another thing that gets over looked is the spring tension on the secondaries. Hope this helps, AL.
     
  5. 71_electra225

    71_electra225 GM > Ford

    Secondary tension

    Well, whats the benefit of tightening the secondary tension? Does that keep the engine from flooding or what?
     
  6. IDOXLR8

    IDOXLR8 Senior Member

    Carburetor Problems

    On the last question, no quite the opposite. The "Q-Jet" is a very virsitile carburetor small primaries and large secondaries and because of the large difference they have a secondary top spring loaded and vacuum dampened top cover to keep from having a lean condition when you open the huge lower secondaries. The way you need to look at it is like controled choke. Hope this helps, AL.
     
  7. GSMAG

    GSMAG Well-Known Member

    The secondary tension is for the butterfly on top, not trhe throttle plates in the base. If it flaps open too quickly, the car will sputter or die. It should not just flip open when floored. Have a look at it when the car is running. Goose the throttle by hand and look at the secondary butterfly. If it flips open quickly, you probably need more tension on it.
     
  8. redbuick

    redbuick Well-Known Member

    Is it a rebuilt carb???, if so they end up with some mismatched parts and can really be a pain. Find a friend who knows Q-jets and let him take a peek, most are easy to fix when found this way..............good luck
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Re: Secondary tension

    The air valves, in effect size the carburetor capacity to engine demand. The secondary side of the Q-jet flows a ton of air. When you floor the gas, if the air valves flop right in, the carb is providing the engine with more air than it can use at low RPM. The engine then BOGS big time. There are two things that control air valve tip in. One is the spring wind up adjustment. The other is the vacuum break on the passenger side front of the carb. It has a link to the airvalves and holds them closed at idle. When you floor the gas, vacuum drops, the vacuum break relaxes and lets the air valves tip in gradually instead of flopping in. If you can push the airvalves open with the engine running at idle, the vacuum break is defective. Replace it.
     
  10. 71_electra225

    71_electra225 GM > Ford

    Thanks guys, im going to take a look at it tomorrow if I can pull away from eating lots o turkey!
     

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