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Lurching/jumping At Low Speed

Discussion in 'Early CJ5 and CJ6 Tech' started by aekdbbop, Apr 23, 2018.

  1. Apr 23, 2018
    aekdbbop

    aekdbbop Member

    TN
    Joined:
    Jul 31, 2014
    Messages:
    403
    K folks, this may just be part of the beast, but I want to find out either way.

    With an f134, cater YF, 5.38s in 2wd high, 1st gear: The jeep seems to lurch or jump forward when applying very light throttle. I can push a little harder and with speed and RPMs, it goes away and everything is normal. Doesn't happen at speed.

    ?
     
  2. Apr 23, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    12,367
    When the beast is tamed (adjusted) properly then it should not behave like that. Metering rod adjustment, float level or fuel delivery/fuel pump, accelerator pump issue should be on your list of suspects. Vacuum leak/low vacuum could give you an accelerator pump issue.
     
    dozerjim and jpflat2a like this.
  3. Apr 23, 2018
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Aug 3, 2003
    Messages:
    9,754
    Possibly the throttle linkage is getting a feedback cycle from engine/transmission motion.

    I would check the linkage adjustment, and engine/trans mounts, and the stay cable to the frame crossmember.
     
  4. Apr 23, 2018
    aekdbbop

    aekdbbop Member

    TN
    Joined:
    Jul 31, 2014
    Messages:
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    Ok, some more info.

    Vacuum is good, did a test.

    the linkage is cable driven, its not the linkage. Ill look at the metering rod and float.
     
  5. Apr 23, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
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    12,367
    Your throttle linkage is cable driven? That's certainly not original, got a picture of that setup?
     
  6. Apr 23, 2018
    garage gnome

    garage gnome ECJ5 welder

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    3,083
    My jeep used to do that. Turned out to be a broken spring in the clutch disc.
     
  7. Apr 23, 2018
    aekdbbop

    aekdbbop Member

    TN
    Joined:
    Jul 31, 2014
    Messages:
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    I used an aftermarket kit you can buy at any flaps. It works well. I’ll snap a few pictures.
     
  8. Apr 23, 2018
    aekdbbop

    aekdbbop Member

    TN
    Joined:
    Jul 31, 2014
    Messages:
    403
    Hope not :/ fairly new clutch


    I think I found the culprit. A loose plug on the vacuum port on the yf.
     
    Glenn likes this.
  9. Apr 24, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

    exploring the...
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    FWIW I used to carry an offset screwdriver to tighten the base screws when my old one would start surging.
     
    aekdbbop likes this.
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