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  1. #1
    Street Tire
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    Has anyone solved the I-5 'near-stall' issue?

    Just curious if there was a known set of problems which cause the I-5 engines to stall, or near-stall at stop signs?

    Mine doesn't quite stall at stop signs, but the engine drops speed and chugs for a second, then recovers. It's done it since I've owned it.

    Yesterday I was looking at the scanner and noticed when I rev the engine up and it revs down, the Throttle voltage dips way down below the normal idle voltage the split second before the near-stall, then the voltage recovers to normal a split second before the engine recovers to normal idle. I didn't write down the voltage readings, but I'd say it was 25% lower voltage than normal prior to recovery.

    Just curious if anyone else had noticed this? I'm wondering if replacing the Accelerator Pedal sensor, or the motorized Throttle Actuator has been shown to resolve the near-stall issue (???).

    I doubt it's the cat as my vacuum is perfect (a bad cat can cause low vacuum). I haven't yet measured the exhaust pressures. However I was seeing a definite correlation between Throttle voltage drop (below normal) and near stall.

    What are your thoughts and experience on this?

    Thanks
    Last edited by Jeepwalker; 03-18-2020 at 09:14 PM.
    Jeepwalker

    '07 H3 Advent/Lux
    Jeep XJ, ZJ, WJ
    Ram & GMC 4x4's
    Toyota Hilux

  2. #2
    Street Tire
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    I have the same issue. No resolution though. Iíve cleaned the throttle body and left the battery disconnected while I changed the alternator. No change in the idle drop, but disconnecting the battery did seem to help the engine shake/vibration while idling in gear. Not sure why, unless itís got something to do with relearning fuel trims.


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  3. #3
    El Diablo
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    The only time I had that issue was when my cylinder head was failing. Not saying that's the issue you are seeing, but I've never had an issue like you described except ahead of the head replacement.

    Sent from my SM-N976V using Tapatalk

  4. #4
    Street Tire
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    What was the issue of the head? I mean the root issue? Were you experiencing low compression or something else?

    Thanks
    Jeepwalker

    '07 H3 Advent/Lux
    Jeep XJ, ZJ, WJ
    Ram & GMC 4x4's
    Toyota Hilux

  5. #5
    Baja
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    Sometimes if I forget to press the clutch I have that problem.

    In all seriousness, I have never had that issue with the H3, but I did have the identical issue in my Silverado (2003 4.8L). Never really did figure out if it was truly the cause, but my battery was failing. Once I replaced the battery, the issue went away. Really don't really know if that was the cause or not but with the funky things that happen on an H3 when the factory battery terminals fail, I'd say it's worth investigating. Good luck!

  6. #6
    El Diablo
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    Quote Originally Posted by Jeepwalker View Post
    What was the issue of the head? I mean the root issue? Were you experiencing low compression or something else?

    Thanks
    Low compression, if I recall correctly. Dealer diagnosed and repaired under warranty

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  7. #7
    Bald Tire
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    vvt solenoid replaced,
    have the idle speed adjust through your tuning mine's running 750ish Rpm at idle,

  8. #8
    Bald Tire
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    Double posted somehow
    Last edited by Rockhound; 03-19-2020 at 02:43 PM. Reason: Double post

  9. #9
    All Terrain
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    New plugs and a through cleaning of the throttle body and maf took care of it for me.
    06 H3 Adv - Great, another project.
    09 H3T Alpha/Adv- Sold

  10. #10
    Mud Terrain

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    Just to point this out. There are electronics in the throttle body. Look for troubleshooting procedures for the TB itself.

    Sent from my SM-G981U using Tapatalk

    Know your Bugs Bunny.... Very important.

  11. #11
    Mud Terrain
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    I raised my idle in the tune and never had that problem. Makes it smoother sitting still too.
    2007 Hummer H3, 3.7L, auto trans, adventure transfer case. Rear locker.
    315/75R16 Nitto trail grappers, Thor parts frt/rr bumpers, 10,500lb winch, OEM rock rails, ucp, rear disconnects, blah, blah, ect.

  12. #12
    Street Tire
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    New plugs and a through cleaning of the throttle body and maf took care of it for me.
    You know ...that's been on my list to check again, but I haven't gotten around to it. Not that we're 'sheltering at home' I have the time. Thanks for the reminder.
    Jeepwalker

    '07 H3 Advent/Lux
    Jeep XJ, ZJ, WJ
    Ram & GMC 4x4's
    Toyota Hilux

  13. #13
    Bald Tire
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    Swap plugs, clean throttle body, and clean map sensor. Worked for me Few hours work and run great. I do this every spring


 

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