1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Jeep Fires But Won't Run

Discussion in 'Early CJ5 and CJ6 Tech' started by Henri Watson, Nov 8, 2021.

  1. Nov 8, 2021
    Henri Watson

    Henri Watson Member

    Mississippi
    Joined:
    Oct 27, 2018
    Messages:
    140
    Well I'm back into jeep mode and I've already got a head scratcher. Yesterday I took my jeep for the first big ride of the season to shake out whatever problems needed addressing before putting it to use all winter, and a few things revealed themselves including one problem I can't wrap my head around.

    For starters my battery was low (pretty sure the alternator isn't charging) so I got one good crank out of it, took a ride, and came back to a dead battery and couldn't get started. I jumped off to another battery and at this point the jeep would fire but wouldn't stay running. I was a little low on gas at the time so I went ahead and put another gallon in there just to make sure it wasn't a fuel problem, but still the same result. I had this problem or at least a similar problem two years ago when the ignition wire from the distributor to the key cluster broke off. I was able to chase that down and replace the wire, but that doesn't look like the culprit this time.

    I'm wondering what other things I can check for other than the ignition wire. I have a mechanical fuel pump as well as an electric pump wired to a switch. I tried running the electric pump simultaneously just in case it was a fuel pressure problem but no luck. The spark plugs and wires are less than 3 years old but I guess it'd be worth checking. I have an HEI distributor... Just trying to think here... Any help is appreciated. Thanks!

    -Henri
     
  2. Nov 8, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    8,226
    Does it "fire" while cranking, but die immediately when the key is returned to the "run" position? Ballast resistor burnt out or a fault in the key-switch or that circuit, if you jeep has one.
     
    Henri Watson and timgr like this.
  3. Nov 8, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    11,491
    How old was the gas that was in the Jeep when you drove it? Don't rule out bad gas or maybe some junk in the gas?
     
  4. Nov 8, 2021
    Henri Watson

    Henri Watson Member

    Mississippi
    Joined:
    Oct 27, 2018
    Messages:
    140
    Yes it dies as soon a the key returns to the run position.
     
  5. Nov 8, 2021
    Henri Watson

    Henri Watson Member

    Mississippi
    Joined:
    Oct 27, 2018
    Messages:
    140
    It has fresh gas, good thought though thanks
     
  6. Nov 8, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,048
    What Pete wrote. The ignition switch bypasses the "run" circuit when you turn it to start. When the switch returns from start to run, that circuit is open and the engine dies. Hot wire it, and see if it keeps running. Then look critically at the ignition switch, starter solenoid and connecting wiring. Most likely a bad ignition switch.
     
  7. Nov 8, 2021
    Henri Watson

    Henri Watson Member

    Mississippi
    Joined:
    Oct 27, 2018
    Messages:
    140
    Thanks, I'll take a closer look at that circuit and see what I come up with!
     
  8. Nov 8, 2021
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2021 Sponsor

    East Tennessee
    Joined:
    Feb 8, 2021
    Messages:
    644
    Had similar symptoms on my CJ5 and in that case it was indeed the switch.

    Walcks has one that actually fits a CJ5. Most other suppliers sell a generic switch they list for a CJ5 which will fit the smaller hole in a CJ2A dash, but does not fit well in the CJ5 dash without a spacer.
     
  9. Nov 15, 2021
    Henri Watson

    Henri Watson Member

    Mississippi
    Joined:
    Oct 27, 2018
    Messages:
    140
    Problem solved sorry to say it was pretty basic! The key cluster was getting loose so it rotated as I turned the key, which broke the connector to the run wire. This jeep stays about an hour and half away from my house in the winter so whenever I have a problem I always end up overthinking things because it's a long way back to the house if I don't have the tools I need! This time it was simple at least.
     
    ITLKSEZ, Fireball and Glenn like this.
  10. Nov 16, 2021
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2021 Sponsor

    East Tennessee
    Joined:
    Feb 8, 2021
    Messages:
    644
    Exactly why I bought a switch that fits.
     
    Henri Watson likes this.
New Posts