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Thread: Couple Duramax Log Questions

  1. #1
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    Default Couple Duramax Log Questions

    I'm helping a buddy try to diagnosis what seems to be an intermittent fuel miss. Looking at the flow rates at idle, the lowest is -2.72 and the highest reads 2.63. Is that a sign that he has injectors going out? Also, when logging a couple full throttle passes to see what it was doing, there doesn't seem like much difference between his Edge Juice w/attitude on 5 vs stock with the Edge totally unplugged from the system. Is that normal cuz the Edge fools the computer to the point where the EFI Live logging tool doesn't see it? Sorry about all the questions but this is the first Duramax I've hooked to and stuff is a lot different than the Cummins stuff.

    Any help is greatly appreciated.
    Thanks
    Attached Files Attached Files
    06 3500 4x4 CCSB - HE351 over S475, Air Dog 165, SBC SFI Dual Disk, and 5" straight pipe.

  2. #2
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    What year truck and any background on performance parts would be great.
    2002 Chevy Duramax with a few supporting mods.

  3. #3
    Lifetime Member THEFERMANATOR's Avatar
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    All the EDGE really does is bump the fuel pressure up, so your not going to see much change in it on any level in a log as the juice is just a plug in fooler. Need to know what the balance rates are, and the fuel rate at idle to tell you much about the injectors.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

  4. #4
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    I left that info out yesterday just in case I got it wrong, but here it is:

    2003 Chevy 2500 4x4 w/LB7
    Stock Injectors
    Edge Attitude "HOT"- one of the early "HOT" boxes
    Blocked wastegate on turbo
    4" exhaust
    Mallory Comp 140 fuel pump
    AFE cold air kit
    ATI Triple Disk converter
    Transgo 1-2 shift kit

    I took some screen shots of the balance rates of the injectors. Let me know if you need anything else.

    I thought the edge was more than just a pressure box, but I guess not. We were in suspicion that the Edge was possibly bad after reading this. Also, the truck seems to idle smoother (doesn't have the intermittent miss nearly as bad as with Edge in the circuit). But, when you look at the balance rates, the rates look worse with the edge out of the system.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    06 3500 4x4 CCSB - HE351 over S475, Air Dog 165, SBC SFI Dual Disk, and 5" straight pipe.

  5. #5
    Lifetime Member THEFERMANATOR's Avatar
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    The numbers in your 2nd pic all look good to me. Your fuel rate at idle is right where it should be, and all your balance rates are well within spec. As for the intermittent miss, has he unplugged teh EDGE and seen if it still does it. The EDGE juice was KNOWN to give alot of quirky issues on LB7's like shuting the wipers off and activating the security system for no reason. And if the wastegate is truly blocked on a stock turbo, that is a recipe for dusaster. The stock turbo can go into an overspeed at much more than 32 pounds of boost and the turbine wheel can let go. The edge may be shutting it down for an overboost situation.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

  6. #6
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    Quote Originally Posted by THEFERMANATOR View Post
    The numbers in your 2nd pic all look good to me. Your fuel rate at idle is right where it should be, and all your balance rates are well within spec. As for the intermittent miss, has he unplugged teh EDGE and seen if it still does it. The EDGE juice was KNOWN to give alot of quirky issues on LB7's like shuting the wipers off and activating the security system for no reason. And if the wastegate is truly blocked on a stock turbo, that is a recipe for dusaster. The stock turbo can go into an overspeed at much more than 32 pounds of boost and the turbine wheel can let go. The edge may be shutting it down for an overboost situation.
    Thanks for that info. The 2nd pic is with the Edge installed and on #5 setting. The first pic is stock, with the Edge unplugged from the system. So yeah, the truck seems to idle better with the Edge unhooked, but it also shows a lot more balance difference at idle too.

    I'll have to ask him about his wastegate if it is fully blocked and if it is, possibly hook the wastegate back up so he doesn't grenade his turbo.

    Thanks!
    06 3500 4x4 CCSB - HE351 over S475, Air Dog 165, SBC SFI Dual Disk, and 5" straight pipe.

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