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Thread: fuel gauge not working, no code flashing

  1. #1
    Join Date
    Dec 2005
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    Klamath falls/keno Oregon
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    Default fuel gauge not working, no code flashing

    full of fuel, gauge reads empty with a light saying its low.

    This is a work truck with 330,000 miles, a ladder rack and tool boxes, hope i don't have to remove the bed.

    thoughts
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  2. #2
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    Default

    A stuck float on the fuel level sender? Can you get to the wiring harness to do some electrical tests?

  3. #3
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    I have a full load in the bed....so getting to the sending unit would be a last resort ( thanks GM for not putting a plate in the bed over the fuel tank sending unit)..
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  4. #4
    Join Date
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    Default

    Not overly difficult to drop the tank. Lines, wiring, filler neck screws, ground strap, then 2 bolts.
    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!

  5. #5
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    Default

    fuel sending unit is $350...I guess I should have one if Im going to lower the tank huh??
    anything else I should get while Im in there?
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  6. #6
    Join Date
    Apr 2001
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    Arrow

    Before you get waist deep into this, be sure it is the sender, and not the gage or communication issue. Use a scanner to read the fuel % level. If it matches the gage, then it's likely the sender. If it doesn't, then it's more likely a gage (IPC) or harness issue.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  7. #7
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    Default

    My tank is full, gauge reads empty and the light is on.

    I have a CanOBD 2&1 scanner.

    am I in the ball park?

    My scanner it seems will only get a code, I have no code..what scanner do I need?
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  8. #8
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    Arrow

    You have a "code reader", not a scanner. A failed fuel level sender won't set a code. THE scanner is the Tech II, what your dealer and some shops use ($$). Other scanners, such as Snap-On, can do much the same. Other devices, including some power programmers (Predator, In-Tune, Hypertech, Edge) have system parameter scanning abilities, and many of them don't require it to be "married" to the truck just for scanning (borrow one from a friend with a similar truck). In all likelihood, the sender is the problem. However, replacing it is a lot of work, to just find out it isn't the problem.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  9. #9
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    Default

    If I remember correctly, there is a way to send a voltage signal to the instrument cluster gauge and test it to see if it is actually sweeping properly. I don't know that exact technique, but I'm sure someone here does.

  10. #10
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    I believe that the sender sends the voltage to the ECM which then drives the gauge so there should be data to read and verify. If this was an early truck I would definitely suspect the cluster, but it seems that the later ones have been much more reliable. Still worth some digging.
    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!

  11. #11
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    Klamath falls/keno Oregon
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    Default

    the 1st thing I noticed was when I filled the tank up, registered 3/4 full then dropped to empty and then went back up to almost full then back down to empty with the warning light lite, and a message saying Im low on fuel.
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  12. #12
    Join Date
    Dec 2003
    Location
    Yukon Canada
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    I just dropped the tank on a 03 that i just bought,not a horrible job.
    But i have a hoist and a tranny jack.My tank was full so i siphoned out most the fuel.My truck was filty dirty and i couldn't wash it,that was the worst part of the job dealing with a dirty truck/tank.
    In your case dropping the tank is the way to go,i had no choice my truck has a wrecker deck on it.
    90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews

  13. #13
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    Klamath falls/keno Oregon
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    Default

    thanks
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  14. #14
    Join Date
    Mar 2000
    Location
    Loyal WI US
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    10,792

    Default

    FYI I just swapped the sending unit potentiometer part from a 2005 Dmax into my daughter's 2007 Impala. It seems that they are the same just different float arms. Plugs in up underneath and locks into the bucket same way. I just shortened the wires to match. I swept it on the car before I reinstalled and it worked, just need to get things finished and go fill up in increments to test it.
    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!

  15. #15
    Join Date
    Dec 2005
    Location
    Klamath falls/keno Oregon
    Posts
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    Default

    thanks, Ill be going to O'Reillys tomorrow.
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

  16. #16
    Join Date
    Mar 2000
    Location
    Loyal WI US
    Posts
    10,792

    Default

    I would recommend OE only.
    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!

  17. #17
    Join Date
    Dec 2005
    Location
    Klamath falls/keno Oregon
    Posts
    466

    Default

    Quote Originally Posted by Kennedy View Post
    I would recommend OE only.
    too late, its on order...
    06 1ton 4X4 duramax/6speed ext.cab WT
    Hummer wheels :^)
    dual lift pump
    Banks air intake

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