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Thread: Fuel cutting out - EQ CMD -> infinity - stock setup

  1. #1
    Tuner in Training
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    Oct 2021
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    Fuel cutting out - EQ CMD -> infinity - stock setup

    All,
    A buddy dropped his truck off, having some issues, where after driving for ~8 minutes, it will sputter and kill (lean shutdown). If you try to start it immediately, it will fire, run for only a few seconds and kill. If however, you let it sit for a bit, fire it back up, it will run for another 5-8min.

    Its a factory 5.3l, swapped into a jeep. I'm fully aware of all sorts of potential issues that could be lurking, but the fact is, he hasn't had this problem in the 3 years the build has been functioning.

    So, I hooked up, took a scan while we drove it around, from cold -- and 8 minutes later, it dies. I then recorded another short scan, after we restarted it.

    When looking at the data, it appears that towards its lean stall, you can see the EQ CMD goes from 1.0 to infinity very rapidly, simultaneously, the injector pulse width goes from 3.0 to 10+, and the STITs from 2.5 to zero..

    I've done the following to rule out some potential concerns -- we did this on the trail...
    1) replaced fuel pump
    2) verified fuel pressure
    3) replaced fuel pressure regulator to be sure (known good one)
    4) replaced cam and crank sensors with known good ones

    I'm wondering why it is killin itself.. and kinda stumped.
    As found.hpt
    LS Fuel cutoff issue - stall at idle.hpl
    shawns truck death 8min.hpl

    Thoughts?
    Thanks,
    Jason

  2. #2
    Advanced Tuner dhoagland's Avatar
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    Jun 2015
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    Aubrey TX
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    Quote Originally Posted by Halfasd View Post
    All,
    A buddy dropped his truck off, having some issues, where after driving for ~8 minutes, it will sputter and kill (lean shutdown). If you try to start it immediately, it will fire, run for only a few seconds and kill. If however, you let it sit for a bit, fire it back up, it will run for another 5-8min.

    Its a factory 5.3l, swapped into a jeep. I'm fully aware of all sorts of potential issues that could be lurking, but the fact is, he hasn't had this problem in the 3 years the build has been functioning.

    So, I hooked up, took a scan while we drove it around, from cold -- and 8 minutes later, it dies. I then recorded another short scan, after we restarted it.

    When looking at the data, it appears that towards its lean stall, you can see the EQ CMD goes from 1.0 to infinity very rapidly, simultaneously, the injector pulse width goes from 3.0 to 10+, and the STITs from 2.5 to zero..

    I've done the following to rule out some potential concerns -- we did this on the trail...
    1) replaced fuel pump
    2) verified fuel pressure
    3) replaced fuel pressure regulator to be sure (known good one)
    4) replaced cam and crank sensors with known good ones

    I'm wondering why it is killin itself.. and kinda stumped.
    As found.hpt
    LS Fuel cutoff issue - stall at idle.hpl
    shawns truck death 8min.hpl

    Thoughts?
    Thanks,
    Jason
    Have you verified fuel pressure at the rail when it dies?
    2011 Camaro 2SS Convertible L99 Bone Stock for now
    2003 Dodge 2500 5.9 Cummins QC 4x4. Airaid, 2nd Gen Intake, Grid Heater Delete, D-Tech 62/65/12, Magnaflow. Bully Dog: Propane Injection, Triple Dog W/Outlook Crazy Larry. Edge EZ, BD Flow-Max, 48RE: Sonnax Sure Cure/Transgo combination, Derale turbulator, billet input, Triple Disc, Super servo, 4 ring Accumulator. :beer

  3. #3
    Tuner in Training
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    Quote Originally Posted by dhoagland View Post
    Have you verified fuel pressure at the rail when it dies?

    Sure have - doesn't appear to be the problem.

  4. #4
    Advanced Tuner dhoagland's Avatar
    Join Date
    Jun 2015
    Location
    Aubrey TX
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    Log your o2 Sensor Voltage
    2011 Camaro 2SS Convertible L99 Bone Stock for now
    2003 Dodge 2500 5.9 Cummins QC 4x4. Airaid, 2nd Gen Intake, Grid Heater Delete, D-Tech 62/65/12, Magnaflow. Bully Dog: Propane Injection, Triple Dog W/Outlook Crazy Larry. Edge EZ, BD Flow-Max, 48RE: Sonnax Sure Cure/Transgo combination, Derale turbulator, billet input, Triple Disc, Super servo, 4 ring Accumulator. :beer