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Quadrajet Gurus, I need your assistance

Discussion in 'The Hokey Ass Message Board' started by DrDano, May 28, 2009.

  1. Flat Roy
    Joined: Nov 23, 2007
    Posts: 533

    Flat Roy
    Member

    Echoing what Budd said. Check the power valve. On a Q-Jet Enrichment of the primary system is achieved by a vacuum actuated piston that actually moves the primary metering needles up and down. Spring tension holds the needles up vacuum sucks them down to lean the engine.There should be a tube aprox 3/8's dia. just in front of the primaries. putting a small screwdriver down that tube you should be able to move the needles with ease. The smallest piece of crud will stop those needles from moving. The engine will idle good if the valves are stuck down but will not accelerate. If stuck in up position ( or any position in between) the engine will idle way rich and be boggy on acceleration. Good luck
     
  2. This is a later model vapor recovery carb. It wouldn't have the vent tubes open on top.
    What you mentioned is a good way to check the enrichment system on the early model carbs.
     
  3. DrDano
    Joined: Jul 10, 2003
    Posts: 696

    DrDano
    Alliance Vendor

    - Changed out the inlet fuel filter. It stank like varnish. The more I snurgled it the more it smelled like old lady perfurme. Bad memories... So that is changed, didn't help at all.

    - Checked the power piston at idle, its all the way down. Engine off its all the way up and I can screwdriver it and it springs up and down without sticking.

    - Started pulling plugs and I think this will be a big factor...if not the issue itself. Wow, these look like SHIT. This is the worst of the 8. Insulators and electrodes caked in white crust that you cant chip off with a finger, but a small hook pick will take it off. Surprised they still fired, never seen a plug like this before. White would indicate super hot and/or lean, correct? Oil on the outside is from my drooling pcv hose on that side.

    [​IMG]
     
  4. ltex old iron
    Joined: Dec 10, 2008
    Posts: 515

    ltex old iron
    BANNED

    everyone i know called them quadraJUNK..i have tried using them and rebuilt them and what not..i havent had much success...they get the job done but after throwing a nice holley on i was much happier
     
  5. Your local gas station will be much happier, too.
     
  6. Nah, it's mostly oil residue. A high output ignition will burn off extra oil for a while til the buildup gets so bad it closes the gap or shorts it out .Then It'll go dead and black.
    Probably valve seals. Any smoke when you start it hot after setting for a few minutes?

    Throw some new plugs in it. Check them in about three months.
     
  7. DrDano
    Joined: Jul 10, 2003
    Posts: 696

    DrDano
    Alliance Vendor

    The engine doesn't smoke at all. Heads are rebuilt with new guides and valves, only a few years old. The oil is on the outside of the plug because my pcv on that valvecover was sweating and it was running down the fins onto that plug. I'm wondering if the plugs were maybe carboned up prior to installing the new ignition and now that CDI ignition is burning it off? I'll replace them anyway this weekend while looking further into the fuel system for wherever this problem is coming from.
     
  8. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    Yep
     

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