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Thread: 2001 duramax massive fuel leak

  1. #1

    Default 2001 duramax massive fuel leak

    I'm new to the forum guys, so be gentle. I have a 2001 GMC Sierra 2500HD Duramax. Its been running great. It has 72K miles on it. The other day it started rather hard and I smelled fuel. I looked under the truck and noticed a rather huge flow of fuel coming down from around the bellhousing. I shut it off and the leak stopped after a few minutes. When I started it again it started leaking again. I cant see where its coming from. Nothing visible from the top and I cant see where it originates from the bottom. Does the fuel line and return line go over the back of the engine?

  2. #2
    NutNbutGMC Guest

    Default

    You may consider doing a serach here on injectors or scan the board.

    In short, that being an LB7 engine, I suspect injectors. The less you spread fuel, the less damage it does to the coatings and wiring harnesses. I had to (also) have the entire wiring harness system replaced. It was saturated as diesel will dissolve most anything.

    You can do a search on my screen name and find a few testimonies of my experiences.

    Sorry about the problem. I think your warranty should cover this unless the timeframe of warranty has lapsed. I may be completely wrong about this issue that you have described but similar symptons that have been written about here have turned out to be said suspected problem.

    Here's a pic of an enroute fuel dump that I experienced.

    .



  3. #3

    Default

    • SES light illuminated?
    • Any white smoke from exhaust lately?
    • Normal oil level?
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  4. #4

    Default

    no SES
    no white smoke
    oil level normal and no hint of diesel smell in the oil

  5. #5
    Join Date
    Jan 2005
    Location
    Southern Indiana
    Posts
    1,177

    Default

    I've seen cracked rails and fuel rail pressure sensors both cause external fuel leaks but without taking some stuff off, it's hard to tell where it's coming from.

  6. #6

    Default

    If it were mine, I'd tow it to the nearest dealership - while diesel isn't terribly volatile - I wouldn't risk starting it again with this much raw fuel present...

    Sure sounds like one of the problems suggested by Madmatt.
    2011 Chevrolet Tahoe 5.3L daily driver
    • Previous owner of two 1994 6.5L K3500s, '01, '02, and '05 6.6L K2500s, '04 C4500, '06 K3500 dually, '06 K3500 SRW, '09 K3500HD SRW, '05 Denali
    • Total GM diesel miles to date : ~950K

  7. #7
    Join Date
    Mar 2007
    Location
    Pacific Northwest
    Posts
    740

    Default

    Sounds to me like the pump itself is leaking. If it still runs, start the engine and look in the valley of the engine in the pump area. See if you see fuel leaking there. I have also seen the high pressure line leak where the fuel exits the pump and heads towards the left fuel rail. Good luck.
    1998 Chevy k-2500 454 147,000 miles and climbing!

    1993 Pontiac G/A Big Block 3.3 Liter 140,000 miles and still going too!

  8. #8
    Join Date
    Mar 2000
    Location
    Loyal WI US
    Posts
    10,792

    Default

    Anybody remember the fuel pressure sensor leaks? Not really super common, and it might be a bit odd that it waited this long to show, but more common than external pump leaks. This issue was oftenbrought to the surface by the addition of psi boxes, but basically it was not tight enough and would suddenly leak/drip as you describe.

    Worth a look. Usually you can do a visual check for the drip on this one.
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  9. #9

    Default

    Thanks for all the help guys. I am gonna have it towed in to a repair shop when I come up with some money. (its tight these days)
    2001 GMC Sierra 2500HD 4x4
    Duramax w/Allison Tranny
    Pacbrake Exaust Brake

  10. #10
    Join Date
    Jan 2005
    Location
    Southern Indiana
    Posts
    1,177

    Default

    If you can verify if it's the FRP sensor,, I'm PRETTY sure I have one laying in the garage.

  11. #11
    Join Date
    Mar 2000
    Location
    Loyal WI US
    Posts
    10,792

    Default

    If you look down from above you can typically see the psi sensor and tell if it is dripping. Go just ahead of the blue boost boot at the compressor outlet. The sensor is in a "function block" and lays horizontally with the connnector facing rearward.
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  12. #12

    Unhappy Fuel Pump

    Well I got my truck in to find out whats causing the leak. It turns out that the high pressure fuel pump was starting to fail and blew out the plug (kinda like a freeze plug) in the bottom of the pump. The mechanic found some metal shavings in the valley of the engine and if you look in the the hole on the pump you can see something is not normal in there. Soooooo, $1050 for the pump, $1200-$1300 for labor and $150 for gaskets I will get my truck back on the road. I only hope that none of the shavings I saw got to any of the injectors.
    Anybody else ever had to replace this pump? For what reason.
    2001 GMC Sierra 2500HD 4x4
    Duramax w/Allison Tranny
    Pacbrake Exaust Brake

  13. #13
    Join Date
    Jan 2005
    Location
    Southern Indiana
    Posts
    1,177

    Default

    WOW, whats their labor rate?

  14. #14

    Default

    i may be wrong on that. i think he said 13-14hrs at $80/hr. works out to around $1100-$1200. GM quotes the job at 16 hrs so i was ok with that. And after seeing the engine with the pump out I can understand why it takes so long. I dont think i could have done it myself.
    2001 GMC Sierra 2500HD 4x4
    Duramax w/Allison Tranny
    Pacbrake Exaust Brake

  15. #15
    Join Date
    Mar 2007
    Location
    Pacific Northwest
    Posts
    740

    Exclamation

    Uhhhhhhh you better have them check the labor time guide again. That pump in the LB7could be done at least three times for the 13-14 hours you were quoted. I realize it was bid at a FLATRATE but there has to be a limit. Did they pull the numbers out of their "BOTTOM?" GM warranty flat rate time pays 4.0 hours plus up to .3 hours to diagnose ::snicker:: Keep in mind, theses are what gm will pay us to repair the vehicle under warranty. 9 out of 10 times it isn't enough. That's why there are Mitchell/ Haines/ Alldata flat rate guides to go by when the vehicle is out of warranty. The times are alot more realistic. Good luck with your pump.
    1998 Chevy k-2500 454 147,000 miles and climbing!

    1993 Pontiac G/A Big Block 3.3 Liter 140,000 miles and still going too!

  16. #16
    Join Date
    Jul 2009
    Location
    Cushing Oklahoma
    Posts
    72

    Cool

    hey deerhunter, dont under estimate your self on doing the work to your truck yourself, i have worked on cat, cummins, detroit, international, my 02 lb7 is like nothing ive ever seen, once i got into it it wasnt that bad, just time consuming. have to replace head gaskets, still have the heads on the bench, parts are very high also, which i'm sure you know by now! (i call it the duramax tax) its like a big jiggsaw puzzle,

  17. #17
    Join Date
    Jul 2009
    Location
    Claresholm AB
    Posts
    6

    Default

    Too many hours for a pump replacement.
    Replacing all 8 injectors is only good for 10 hours!
    Do it your self, or find another shop!

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