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Turn up the pump

Discussion in '1982-Present GM Diesel' started by Russell Keys, Sep 29, 2002.

  1. Russell Keys

    Russell Keys 1/2 ton status

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    Where is the fuel rate screw on the injector pump on a 6.2? Has anyone turned theirs up? Does it make a diff? I remember seeing a while back in one of the mags...101 things to do to a chevy, and turn the fuel screw 1/16? of a turn helps with some power w/o hurting the engine. Just a thought.
     
  2. Tybee

    Tybee 1/2 ton status

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    Dont know where its at but I know people do it when the put turbo on.
     
  3. Txstruck

    Txstruck Registered Member

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    Never heard of one, but you can adjust the injector timing. Kinda like adjusting the distributor on a gasser.
     
  4. ben427

    ben427 1/2 ton status

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    yeah, but you gotta know what you are doing or you can end up in meltdown mode. you have to tae the cover off the pump, adn its a little allen screw, it turns real hard.really a hair under a 1/16 would be safer, and installing apyrometer would help too. keep the egt under 1000 and youll be optimum.
     
  5. arveetek

    arveetek 1/2 ton status

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    The fuel metering screw is located underneath the top cover of the injection pump. Here is the procedure:

    1. Remove the top cover (3 smalls screws)
    2. Siphon or out fuel. Keep er clean.
    3. Rotate engine (without starter) by belt or hand until allen-head screw can be seen on rotating pump head inside the pump body. It will be down under the springs and linkages that are the throttle.

    Note: Notice I said without starter. The truck will start and run just fine without the top cover on.....)

    4. Use a 8mm allen to rotate clockwise the screw. For non-intercooled vehicles, rotate about 1/4 turn (point allen at 12 o'clock, rotate to 3 o'clock). For max power on intercooled powerplants rotate half turn (to 6 o'clock)
    5. Ensure no debris is inside pump body and re-install cover. Careful that the stop selenoid mechanism is not binding.
    6. Road-test. If EGTs are high, reverse the procedure by turning pump down some.

    These instructions are for a 6.5L turbodiesel, but apply just the same on a n/a 6.2L. I have the pump turned up about a 1/4 turn on my '81 6.2L n/a.

    I'd suggest you also install a pyrometer before messing with the fuel delivery too much. You don't want to melt the engine down, 'though I don't think it's nearly as much of a problem in a n/a engine. I've seen temps in excess of 1400 degrees while towing with my engine, and that's meltdown temps for a turbocharged motor.

    If you aren't confident about what you're doing, hire somebody to adjust the pump for you. A local diesel shop near me charges $35 to turn the pump up. It does increase the power quite a bit.

    Casey
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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  7. Drey

    Drey 3/4 ton status

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    Does mileage decrease with this mod much? I would almost thing mine might go up. The TC could stay in lock up and wouldnt kick down on the hills or in high winds so much I would think.
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Should only hurt if you're into the throttle more. Cruise fuel rate shouldn't change any. My '83 is turned up, not sure how much but it'll smoke from the exhaust at 1/2 throttle or less...WOT leaves a pretty impressive trail of black smoke. I drive it normally though and manage around 18 in town and 25 on the highway.

    Paul had a shop install a rebuilt IP, and they decided to do some mods while they were at it. I found the EGR cleverly disabled, 'J' code intake gaskets with the EGR port block offs intact, and a pretty obvious increase in fuel rate. I found all this when I did head gaskets, and after talking to Paul it was apparent the shop did this on their own...Paul had no clue, wasn't asked and didn't pay extra. As far as he knew it was all dead stock.

    My K5 on the other hand barely smokes even at WOT...

    Mine still hunts a bit on hills though. There are several areas I just drop it down into drive to solve that issue.

    Rene
     
  9. thedrip

    thedrip 1/2 ton status

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    I just turned mine up this morning. only 1/8th turn, seems to be plenty. I have a c-code IP on a j-code motor, so the engine was already breathing better, and I recently installed a free flowing exhaust. If you're going to try this, use the top cover method. you can do the whole mod in under 15 minutes, don't need a dentist's mirror to do it, and you'll swear a lot less.
     
  10. AJMBLAZER

    AJMBLAZER Better to be lucky than good. Premium Member

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    Either of you guys have an EGT gauge or are you just winging it?
     
  11. joez

    joez 1/2 ton status

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    My old 6.2 was running a J-code intake, open element air cleaner, 6.5td injectors and had some pump mods. I could see 1400° pretty easily from the passenger side manifold. She sure smoked a lot, and for whatever reason after a fuel filter change it would literally POUR black out the tailpipes for about 10 miles, like to the point it would actually leave two sootstains on the pavement behind you if you punched it right after you pulled out of the driveway. Even the guy i sold it to had this issue(until the motor blew up), neither of us were ever able to figure out what caused it.
     
  12. thedrip

    thedrip 1/2 ton status

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    no EGT gauge... I use the truck almost exclusively offroad/in town, so it never sees more than a few seconds of WOT anyway. I also only turned the screw 1/8th turn. I could go a little further, but something on 42's just only needs to be so quick. I'm just not that worried about EGT's. it'd be an excuse to swap in a 6.5TD
     
  13. Drey

    Drey 3/4 ton status

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    My truck will only smoke just a tad in 1st and 2nd at WOT...nothing in 3 or OD

    My K10 would smoke in any gear
     
  14. Mikey von

    Mikey von 1/2 ton status

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    I cannot get my suburban to smoke at all. I was pulling almost 9000 lbs yesterday up some large hills and no smoke at all. I think I need more fuel and my timing is off. I have a banks turbo in my garage, but would not mind adding a little more juice before I do the turbo. I plan on rebuilding injectors and IP, new exhaust, and replacing the timing chain with gears when I do my turbo.

    My question is can I put a EGT gauge on now and reuse it when I do my turbo with new exhaust? I want to turn up my fuel, but cannot afford a melt down right now.
     
  15. AJMBLAZER

    AJMBLAZER Better to be lucky than good. Premium Member

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    Mine barely smokes on start up and that's about it. Since I started using 4x4xGod's diesel additive instead of the store stuff + ND30w the slight bit of smoke I was getting is pretty much gone.

    The EGT makes me a bit nervous so I think I'll just sit on this until after we've sold the house and moved. Need it running.
     
  16. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    No EGT guage on mine either...but quite frankly if it's not seen WOT more than 3 times in the last year or so, and even then it's maybe a short burst. If I towed with it I'd want one for sure.

    Rene
     

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