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EGR knockouts on intake gasket

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, Apr 3, 2003.

  1. 90K5

    90K5 1/2 ton status

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    dont know why i didnt do this, but when i replaced my intake gasket, there were some knockouts in the new one for the EGR...i guess that gasket PN is good for non EGR trucks too...thing is, i didnt cut them out. no idea why i didnt, i guess i was just tired. Anyway, what will this cause? just no egr? is there anything i have to worry about? seemed to run about the same before and after replacing the gasket, but will this cause any problems? thanks
     
  2. milspecjimmy

    milspecjimmy 1/2 ton status

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    it will eventually burn out the material, but for now till that happens, you will get worse gas mileage at highway cruising.
     
  3. 90K5

    90K5 1/2 ton status

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    thats ok with me....its barely running right now anyway. just as long as it wont cause any problems
     
  4. wrathORC

    wrathORC 1/2 ton status

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    It just won't heat the intake, that's all. If you have an exhaust diverter valve it'll cause problems because the diverter will try to force exhaust through the intake. I don't know if your K5 has one but my 84 K10 did on the passenger side.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Good point, better make sure your truck doesn't have EFE (or at least hooked up).

    Since EFE essentially blocks off the passenger side exhaust manifold dump when the engine thinks its cold, if you were to block off the heat riser, you'd probably see some real problems, especially at higher RPM's wihtout the engine fully warmed up.
     
  6. 90K5

    90K5 1/2 ton status

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    EFE? What exactly is that? If its what I think it is, i dont have it...isnt it that valve on the exhaust manifold that opens under certain conditions? All i have it the flexible piece that goes from between the #2 and #4 plugs up to the air cleaner, and it just takes the heat from the exhaust manifolds and sends it back to the aircleaner.
     
  7. Itali83

    Itali83 1/2 ton status

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    Your truck does not have the EFE that runs through the intake manifold. The only EFE system you have is the heat riser which you notice that you have. As for blocking off the egr passage you've done the following.....
    Raised the combustion temperatures quite a bit which will result in pinging while cuising or light acceleration, and the detonation will make you loose power and also do damage over time.
    Now since your motor can't use the rich exhaust gasses(compared to just plain old air) it'll have to dump more fuel in and lowering your gas mileage.
    If I were you, I'd take the intake off and fix it, The EGR will not lower your performance so that you'll notice it and it's needed to keep the combustion chamber cool like it likes.
    Ben 87 Jimmy + 89 Blazer
    /forums/images/graemlins/usaflag.gif
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah you are correct..exhaust "blockoff" valve in the passenger side manifold, if so equipped.

    Not surprising GM didn't use one, some TBI camaro's that vintage(at least) were the same way.
     

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