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vaccum advance

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 83bowtyblazer, Sep 24, 2001.

  1. 83bowtyblazer

    83bowtyblazer 1/2 ton status

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    Hi guys, does anyone know what the vaccum pressure is supposed to be on a vaccum advance?? When I suck on the vaccum line, it doesn't move usless I help it. I have a "knocking under acceleration" problem too. My timing is set at +28 degrees right now, to give me better throttle response. Any ideas??

    Ryan

    Never knock on DEATH's door. Ring the bell and run...he hates that!!!!
     
  2. POWERMAD

    POWERMAD 1/2 ton status

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    28* no wonder it pings.
    back it down to around 6* and get another vacuume advance.
    It should move as soon as there is vacuume.

    <font color=green> Too bad ignorance isn't painful </font color=green>
     
  3. blazer72

    blazer72 1/2 ton status

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    Whats that I just dial it in on the laptop and go on.
     
  4. Burbinator

    Burbinator 1/2 ton status

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    28 degrees? At idle? I bet it runs like crap and pings like a mother with that much advance! Back it down to 6 or 8 degrees @ about 500 rpm with the vacuum advance line disconnected and plugged, reconnect it when you've set your base.

    - Alan

    '82 K10 Suburban Silverado (AKA U.S.S. Nimitz)

    Terrorists are good for one thing...FERTILIZER

    GOD BLESS AMERICA!
     
  5. 83bowtyblazer

    83bowtyblazer 1/2 ton status

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    It runs great at idle. It does have a little bit of a hard time starting when it's warmed up though. When you get on it real hard, that's when it knocks. OTher than that, it's fine. I disconnected and plugged the vaccum line for the advance and set the timing at about 8 and it has extremely sluggish throttle response. The only way to get a good throttle response is with the timing set at 28 or so.

    Ryan

    Never knock on DEATH's door. Ring the bell and run...he hates that!!!!
     
  6. slider79blazer

    slider79blazer 1/2 ton status

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    mine is set kind of hi like that but mine back fires through the exhaust. I think mine is a vacuum leak I'm trying to track it down. I think it's my EGR valve. if your vacuum advance isn't working i would buy a new one for the distributor.

    <font color=blue>whats a 4 letter word for farm wagon?-- ford</font color=blue> [​IMG]

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  7. Triaged

    Triaged 1/2 ton status

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    Make sure your mechanical advance is not frozen.

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  8. 83bowtyblazer

    83bowtyblazer 1/2 ton status

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    The distributor is brand new. Everything in it works fine except for the vaccum advance.

    Ryan

    Never knock on DEATH's door. Ring the bell and run...he hates that!!!!
     
  9. 83bowtyblazer

    83bowtyblazer 1/2 ton status

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    Anyone else have any input???

    Ryan

    Never knock on DEATH's door. Ring the bell and run...he hates that!!!!
     
  10. Highlander

    Highlander 1/2 ton status

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    When you set the timeing pull off the vac. line to the dis. and plug it set you timeing about 8 deg up to 12 deg I run mine at 10 deg then if you have a vac. gauge use it to set your idle mixture screws to the highest vacuum. then put the vacuum hose back on. Now you know that there is a knock senser on the right hand side of the block. hope this helps out Eric

    <a target="_blank" href=http://cethern.tripod.com/erics-home-page-and-other-stuff/>http://cethern.tripod.com/erics-home-page-and-other-stuff/</a>
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  11. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    I know this probably isnt it but is the distributor in sync with no.1 cylinder. When i dropped in my first distributor back when, I messed up and had the rotor pointing to 8 instead of 1 at TDC. It ran kinda like yours. Of course I ignored something I couldn't have possibly done when I was having trouble but I pulled the cap anyways and that was it.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  12. 83bowtyblazer

    83bowtyblazer 1/2 ton status

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    How do I check that?

    Ryan

    Never knock on DEATH's door. Ring the bell and run...he hates that!!!!
     
  13. POWERMAD

    POWERMAD 1/2 ton status

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    Bring the # 1 cylinder to TDC pull the cap and see where the rotor is pointing.
    #1 will be in the front next to where the distrubutor sticks out for the wiring, #8 is next to it on the left.


    <font color=green> Too bad ignorance isn't painful </font color=green>
     
  14. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Yup, what he said. All the plug numbers are stamped on the manifold. Pull your #1 plug (driver's side, front) and stick your finger in the hole, thats right, plug the hole. Then have a buddy bump the motor till you feel and hear and woosh come from the hole. Then put a wrench on the front of the engine (big pulley at the bottom with the balancer) and move the motor till its on 0 degrees TDC. Then just follow your plug wires to your distributor cap. Note where the no.1 wire goes on the cap and pull the cap off. If set correct the end of the rotor will point right under where the no.1 wire is.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     

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