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I am NEVER this lucky!!! Comments on Motor question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by zakk, Oct 23, 2002.

  1. zakk

    zakk 1/2 ton status

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    The Black Bear was running a bit rough the past few days. So i popped the hood, made sure all the vaccum caps, fittings, etc. were tight. I decided to "flip" the stock air cleaner lid (I but it back to "stock" for a failed smog check).

    After doing all this, i fired it back up, and spun it around the block and it was MUCH BETTER!

    It was hesitating and backfiring a bit, the snorkle on the stock air cleaner is 2" in diameter.

    Could this extra air be what it needs to run right?
    /forums/images/graemlins/ears.gif
     
  2. kennyw

    kennyw N9PHW Premium Member

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    Is there a flap in the stock snorkle? It could be stuck closed or the vacuum line up to it may be hooked to the wrong port? Possibly the heat switch that is supposed to run the vacuum is faulty? Just some ideas since I cant see it...
     
  3. HarryH3

    HarryH3 1 ton status Author

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    I'm with kennyw on this one. It sounds like the thermal flap that helps the truck warm up quicker and also keeps the throttle body from icing in cold weather is either stuck closed or is flopping around. The return spring broke on that flap on my S-Jimmy and the engine would do all sorts of bucking as the door flopped open and closed. Once I got the revs up, it would run fine. But leaving a stop light, especially in cold weather, it looked like I had a standard trans and didn't know how to use the clutch. /forums/images/graemlins/wink.gif I think that when the door would slam closed, it would make the MAP sensor see a high vacuum signal, as if the throttle blades were closed. So the ECM would get very confused... /forums/images/graemlins/confused.gif
     
  4. zakk

    zakk 1/2 ton status

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    can you please explain where the "heat switch" is? i have never head of this part.

    I am not running a Hot Air Stove Pipe...that is the part that had to be axed because of the header swap /forums/images/graemlins/crazy.gif
     
  5. Derf00

    Derf00 1/2 ton status

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    That could definately be your problem running the stock air cleaner. The thermal flap Harry is talking about is inside the air-horn on the stock air clearner. When the engine is cold, the flap is closed and the air is drawn up through the "stove" pipe off your exhaust manifolds, and as the engine warms up the flap opens and the cooler air is drawn in.
     
  6. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    in the metal part where the air comes in ,is there a vaccum line anywhere ? that is the heat switch , it closes to suck the warm air off the exhaust manifolds which you dont have anymore
     
  7. zakk

    zakk 1/2 ton status

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    it does have a vaccum hose. so it sounds like an air cleaner problem. I guess i'll just run the air cleaner flipped until the part comes from Hooker to retrofit my headers to Hot Air.

    thanks everyone!
     
  8. 70~K5

    70~K5 1/2 ton status

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    Zakk I got the part to hook up hot air. Don't need it anymore as '70 doesn't need to be smoged.
     
  9. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Zakk, I hope you didn't pay too much for that part! All it is is a little peice of pipe with two tabs welded to it to hose clamp it to a header pipe... /forums/images/graemlins/thumb.gif You can make one in about 10 minutes with scrap material. </font color>
     
  10. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    You know that anything from hooker wont be cheap. I installed headers on a truck years ago and just cut a small piece of exhuast pipe the correct diameter and tack welded it to a header tube.
     
  11. zakk

    zakk 1/2 ton status

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    that would have made too muh sense for me to do it myself /forums/images/graemlins/crazy.gif

    maybe i'll give that a go this weekend /forums/images/graemlins/thumb.gif
     
  12. 70~K5

    70~K5 1/2 ton status

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    Hey Zakk I said I have that part, come and get it, I don't need it now. /forums/images/graemlins/grin.gif
     
  13. zakk

    zakk 1/2 ton status

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    PM me your phone number. I'll try to get over there this weekend to get it.
     

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