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Vacuum Advance

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by josephn, Nov 20, 2000.

  1. josephn

    josephn 1/2 ton status

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    Should you connect the vacuum advance on the distributer?
    Are there any problems with not having it connected?
    Thanks
    Joe.
     
  2. Emmettology 101

    Emmettology 101 3/4 ton status

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    If it is not connected, then the "Vacuum Advance" wont work.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  3. sosamantx

    sosamantx 1/2 ton status

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    <font color=blue>If it is your stock distributor and motor, then you should leave it connected. If not you will lose performance, part throttle gas mileage and driveability. You would lose performance until all of the mechanical advance has kicked in (probably @3000-3500 RPM'S, not sure exactly), and your gas mileage, as it is not running properly at part throttle, or until all of the advance kicks in. Bottom line, more than likely you would lose power off of the line. You could up the initial advance to the point (when you set the timing, and then you plug in the vacuum advance, the line jumps way up) where the timing line is at (what I said just previous). But I would not recommend this for a stock application, and I don't know why anyone would want to do this, except maybe on a high performance motor. - Steve</font color=blue>

    <font color=blue>Steve Sosa a.k.a. "sosaman"</font color=blue>
    http://sosaman.home.texas.net/carpics.html
     
  4. josephn

    josephn 1/2 ton status

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    Thanks,
    The question was for my brother in law who just bought a new truck that didn't have it connected and I wasn't shure why they would have disconnected it. He has been complaining about his gas mileage so maybe this will help.
    Anyway thanks again.
     
  5. LAZYMON

    LAZYMON 1/2 ton status Premium Member

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    You disconnect it to set timming and they probably forgot to reconnect it

    Topless73
     
  6. TX Mudder

    TX Mudder 1/2 ton status

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    There are three kinds of advance. Mechanical advance, controlled by springs and weights inside the distributor. Vacuum advance, controlled by engine vacuum through a vacuum line. Initial advance, controlled by how much you turn the distributor before you tighten the hold-down nut.
    When you set timing, you disconnect the vacuum advance and a tech probably forgot to reconnect it.
    -- Mike
     
  7. josephn

    josephn 1/2 ton status

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    Thank for your answers. You guys rock.
     
  8. CAPTAINK5-CT

    CAPTAINK5-CT 1/2 ton status

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    Mine went bad and caused the truck to hesitate on pulling away from stops (scary at busy intersections). Had my mech fix it and all is well.
     

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