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remove the EGR valve for power gain?

Discussion in '1982-Present GM Diesel' started by Russell Keys, Sep 18, 2001.

  1. Russell Keys

    Russell Keys 1/2 ton status

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    Has anyone removed the EGR valve from the intake to increase air flow? Did it make a difference?
     
  2. fender

    fender Registered Member

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    You might be able to remove it, but I'm not too sure on that. I think you would be better off finding an intake manifold of a 6.2L that came from a 1 ton. The J code intake manifolds (from 1 ton trucks) don't have an EGR valve. They bolt up to the C code engines (6.2L from blazers, 1/2tons and 3/4 tons). The new intake should give you a couple extra hp and a few more ft-lbs of torque.

    -fender-
     
  3. Oblin Goblin

    Oblin Goblin 1/2 ton status

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    Don't remove the valve. Just disable it by disconnecting the vaccum tube the connects to it. With the valve closed and in place it blocks the EGR passage in the intake manifold. If you remove the EGR valve exaust will be free to enter the intake manifold. If you can find a heavy duty intake manifold your better off using that.
     
  4. Russell Keys

    Russell Keys 1/2 ton status

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    Yeah, I read in a mag where they said to find one off a 1 ton w/o the egr. I haven't looked at the egr close but i thought I could take it off and if needed put a block off plate over the opening. As for the intake I don't think i want to get involved with replacing it now. How hard are they to find and how much do they really help? Also what good would unplugging the hose from the valve do? It's still in the way?thanks for the help, Russell.
     
  5. Oblin Goblin

    Oblin Goblin 1/2 ton status

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    I think the biggest gains will be had if the egr valve is deactivated, which is where disconecting the vaccum line comes in. The valve needs vaccum to open. I don't think removing the valve and blocking off the hole will help airflow much. Even getting a heavy duty intake probly won't produce a noticeable effect unless you do it in combination with a bunch of other little tweaks.
     
  6. Russell Keys

    Russell Keys 1/2 ton status

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    Thanks for the input. I'll deactivate the egr in the morn and drive and see if I can leave black marks down the street(he-he). One more ?, I was always told a diesel doesn't produce vacuum, but there's not a vac. pump on a 6.2?Thanks again, Russell
     
  7. Tybee

    Tybee 1/2 ton status

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    Yes there is a vacuum pump on a 6.2 it sits in the back kinda like a distributor.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  8. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Yes, there is a vacuum pump on your 6.2. It's located in the same spot as the distributor on a gasser............


    <font color=blue> WE WILL NEVER SURRENDER<font color=blue>
     
  9. Russell Keys

    Russell Keys 1/2 ton status

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    AH-HA! Now I know... The rest of the story. Thanks for clearing that up.
     
  10. ZuluNashun

    ZuluNashun Registered Member

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    So... What exactly and where exactly is the egr valve? I have a 6.2 but know nothing about other than to use diesel for fuel and it has glow plugs instead of spark plugs.
     
  11. Tybee

    Tybee 1/2 ton status

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    EGR, Its for the emissions it recirculates the unburned fuel into the intake instead of sending it out the tail pipe. On the 6.2 its located right in the top of the intake manifold. Take off the air cleaner cover and look in the center it has a vacuum line attached to it.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  12. Danno

    Danno 1/2 ton status

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    Curious to hear how disabling your EGR went for you? I'm about to try this out myself, and thought I'd ask you how your engine's running without the EGR functioning?

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  13. Russell Keys

    Russell Keys 1/2 ton status

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    I personally didn't notice a difference with it disconnected. At first I thought I noticed a diff. but that was just wishful thinking. I did take a piece of that black plastic 4" corrugated drain pipe and made a homemade "ram air" with it. It seems to help on the highway when there's some speed involved. Worked for me, esp. in the morn when it's a little chiily. It likes to suck that cool air and it sounds a little meaner too. I read about the intake hose deal somewhere in another post but don't remember where.-Russell
     
  14. Danno

    Danno 1/2 ton status

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    Ah, cool. Thanks for the reply!

    Guess I'll give it a shot tomorrow morning before I head out for work.

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  15. Danno

    Danno 1/2 ton status

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    Wow. That's all I've gotta say. Wow.

    I disabled the EGR on my engine yesterday, and this thing feels like a completely different engine now! Tons more torque, zero black smoke (unless I nail the go pedal from a stop), and it definately runs better in the mountians.

    With the EGR working, my engine seemed to run cooler, grey smoked while idling first thing in the morning, took forever to heat up, and really, REALLY lacked power. I couldn't accelerate in OD even if I was already going 50mph.

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  16. Tybee

    Tybee 1/2 ton status

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    Ill have to try that, did you plug the hose

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  17. Tybee

    Tybee 1/2 ton status

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    I just disconnected mine and noticed a power increase and it now really shifts hard from 1st to 2nd. Now that I think of it when I replaced my head gaskets, the intake gaskets were from the heavy duty 6.2 and had the egr port blocked. The egr valve was still connected, maybe thats how the previous owner got around a visual inspection when taken in for emissions, and still had the power. And me being the dumb arse I put the original gaskets on.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  18. Danno

    Danno 1/2 ton status

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    I just pulled the hose from the EGR, and plugged the hole in the air filter pan where the hose went. Used the hose to plug the other leak I was having. :-)

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  19. RLBstein

    RLBstein 1/2 ton status

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    Just a little explanation of how that EGR valve works. I'm happy you guys notice a power increase in your trucks after disengaging the EGR, I kinda feel the same way when I wash and wax my truck. Anyway, at idle, the EGR valve is open to let exhaust flow into the intake manifold to help warm it up quicker and once you give it 15 degrees of throttle, it closes and stays closed while driving. 15 degrees of throttle isn't very much and it closes the valve pretty quick (I know because I watched it one day). I had the opposite problem with mine. The EGR valve was stuck open and I was blowing chunks of black smoke on accelaration and it completely clogged my air filter w/ black soot. You might even notice a transmission change if you mess with the EGR valve because it controls your TCC (Torque Converter Clutch). Inside that EGR solenoid is a diode for radio-noise suppression and if it goes bad, while cause the transmission to slip, the glow plugs to not come on, and a few other things.

    I'm not an expert at this, and could be wrong on some of it, but i've spent a long time troubleshooting a no glow plug, heavy black smoke, and horrible transmission problem and have finally traced it down to this $80 EGR soleniod.

    85 Blazer on an 82 chassis, 6.2L Diesel, ORD flip, 35's on a 4" lift.
     
  20. Danno

    Danno 1/2 ton status

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    Interesting.

    With my EGR connected, my truck spews smoke, doesn't accelerate well (or at all in OD), and gets poor milage.

    With the EGR disconnected, the truck doesn't smoke at all, accelerates very well through all the gears, and uses much less fuel.

    Now, you tell me what's up! :-)

    The truck is stickered as a "low altitude" engine, and I'm in Colorado. I know there's a different injector pump for low and high altitude use, but are there any other differences?

    By no means am I an expert on this 6.2L diesel engine. I'm open to suggestions if anyone has any ideas on how I can get my truck to run good with the EGR connected.

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     

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