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134f, Won't Rev Past 1500-2000rpm, Intermittent Miss,backfire?

Discussion in 'Early CJ5 and CJ6 Tech' started by 70cj5134f, Oct 10, 2018.

  1. Oct 10, 2018
    70cj5134f

    70cj5134f Member

    East Tn
    Joined:
    Aug 18, 2018
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    749
    Spent half day yesterday, trying to find my miss?
    It started 3 days back.
    Jeep started and drove fine sun night.
    Monday would not start. I unhooked the msd box and went back to points,
    started,ran 30 sec,died. Cut tack wire(I've had them kill ign berore),started ran 30 sec, died.
    Changed coil, started ran ,drove bout hour off and on, on the farm,thought I was done.
    Tue, would not start,changed coil again,cap off dist,green stuff on points,filed them,
    Started ran 30 sec, died. Replaced points,cond,with new, started, idled but won't rev past 1500rpm.
    Miss and pop then. Pulled plugs,cleaned them, still no rpm, still pops.changed plug wires, same?
    Advanced and retarded timing, same.
    What am I missing? It has no chain,so it Coullnt jump time. Valves were adjusted early summer.
    When running and idling it just feels weak. Starts missing and poping bout 1500rpm.
    Dist shaft tight,no play. Cap and rotar look good. I'm at my wits end?
    Ideas?
     
  2. Oct 10, 2018
    ojgrsoi

    ojgrsoi Retired 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Weatherford, TX
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    Fuel, delivery or filter?
     
  3. Oct 10, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Aug 18, 2018
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    Unhooked line at carb, put in gal jug,started at idle,filled jug half up in no time?
    I'll pull carb next? Clean and blow out.
     
  4. Oct 10, 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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    Did you actually set points and timing to spec? At the same time?

    Cap and rotor are cheap enough, and good insurance against high voltage tracking.
     
  5. Oct 10, 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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    That's good, but tells you nothing about static pressure, which should be 2.5-3 psi.
    Had this happen when squirrels plugged my exhaust system with acorns.
     
  6. Oct 10, 2018
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Spark or fuel.

    Sudden vacuum leak, too lean? Idle circuit is separate from the main circuit. IIRC the YF is a needle carburetor, and richens/leans mixture by lifting or lowering the needle.

    Won't a plugged exhaust show up as low engine vacuum?
     
  7. Oct 10, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Aug 18, 2018
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    Carb comes off tonight?
    It acts like lean, pluged passage?
    I just had off couple months ago and cleaned.
    Pretty sure 2 or 3 things were going on at same time?
    All started after sitting a week while I was at beach?
    First coil was bad, points were green, and 1 plug wire was bad, all needed changed anyway.
    Let one set for a week, and it goes all to he%%.
     
  8. Oct 10, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    You're correct, no timing chain but it does have a fiber timing gear.
     
  9. Oct 10, 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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    Yes.

    And vacuum gauges are really really inexpensive.
     
  10. Oct 11, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Carb off and clean, no difference.
    Exhaust open.
    Took a coil off a running truck, tried it, no difference.
    Idles smooth then when u try to REV, misses and sputter.
    With timing light as a scope, one plug wire at a time,
    Light works at idle, try to REV it, light skips a lot.
    On all 4 cyl.
    Gotta be something in distributor?
    It comes out for inspection tomorrow.
     
  11. Oct 12, 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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    Before you pull it, you can check the distributor shaft for side play/worn bushing. That plays havoc with dwell (point gap), and makes accurate setting impossible. A dwell meter may be a good investment.

    Also, are your centrifugal advance weights and springs functioning freely?
     
    70cj5134f likes this.
  12. Oct 12, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Sure sounds like ignition- a lot of "new" condensers are bad right out of the box.

    Also, were the new points the same style as the old? i.e. do the new ones have a separate spring leaf? I've been fooled by those before, if not installed correctly the points will bounce at anything off idle.
     
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  13. Oct 12, 2018
    TonyM

    TonyM Member 2023 Sponsor 2022 Sponsor

    Middle Tennessee
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    I had similar issues with my '56... Intermittent starting and idling issues and sputter and loss of power at the upper end of 2nd gear... After months of chasing, it ended up be a combination of a couple things. Starting issue was a loose connection under the dash on my ignition switch that I should have caught right off the bat. Also, the distributor needed to be rebuilt as I couldn't get the dwell figured out and set. Turns out the weights and springs needed replacing. With the distro rebuilt, points properly gapped and the timing set she runs like a champ. Prior to figuring out what was really wrong I replaced points, condenser, plugs, wires, coil, rebuilt the carb and rebuilt the fuel pump as well. All of this needed to be done anyway (I rationalize) as the rig was new to me and needed some basic TLC and a tune-up, but the loose connection and the distro issue had me baffled so that I just let her sit in the garage for months collecting dust. Very frustrating, but also a learning experience that I needed.
     
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  14. Oct 12, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I agree with Howard about the ignition thought. The above sentence has to be a clue.
     
  15. Oct 12, 2018
    dozerjim

    dozerjim Member

    western New York
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    x2,
     
  16. Oct 12, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Checked the shaft when trouble started, no play.
     
  17. Oct 12, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Had 2 different condenser on it, same results.
    New points had the helper spring.
     
  18. Oct 12, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Aug 18, 2018
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    Ran jumper wire from bat to + on coil, no difference.
    Only thing I can see with it in engi e is the little bolt that holds the
    Coil wire,condenser wire ,and points is buggered up some?
    May be grounding out their.
    Coming out for inspection today.
    What's y'alls pick on a new dist?
    Is the pertronics conversion duriable?
     
  19. Oct 12, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    You could be on to something about the bolt grounding out, maybe bad insulation too.
     
  20. Oct 12, 2018
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    I had the carter on my '57 that was worn out badly enough that I had a dead spot I couldn't futz with enough to get rid of. Hated getting past ~1500ish unless I did it REALLY slowly or just right.

    A Solex fixed the issue and then some.

    Spark side was fine.
     
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