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Start Up And Turn Off

Discussion in 'Early CJ5 and CJ6 Tech' started by CarlGes, Jan 2, 2020.

  1. CarlGes

    CarlGes New Member

    Hi all,
    Not an auto tech but can stumble through a diagram easy enough. I got my hands on a new wiring harness for my 1959 CJ5 but its wired for a generator/voltage regulator. My jeep has a delco remy alternator (SI10 I believe) I am trying to figure out how to wire this up CORRECTLY and reliably. I have found several diagrams and all say something different. After some trial and error I was able to get power to the instrument cluster, start the engine but it will not turn off. Please help. Thanks.
     
  2. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    The excite wire to the alternator from the ignition switch stays high when the alternator is spinning. This back-feeds into the ignition switch, so when you turn off the switch power now comes from the excite connection and the engine does not shut off.

    There are at least 3 ways to deal with this. Jeep uses a resistor (nichrome wire) to the excite connection. The resistance is small enough to excite the alternator on startup but large enough to strangle the ignition when you turn off the key. Instead of a resistance wire, you can use an _incandescent_ bulb in the excite wire. This has the added advantage that the bulb becomes the "alternator light" which signals a defect if the alternator fails to charge. Or, you can put a diode in the wire, so that the current can only flow one way in the excite wire, preventing back-feed.
     
  3. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Essentially you're moving from this
    genny.gif

    To something like this-

    Alt_conversion.gif
     
    Last edited: Jan 2, 2020
    Jw60, timgr and Twin2 like this.
  4. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Howard's attachment does not work for me.
     
  5. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

  6. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    A-ok!
     
  7. CarlGes

    CarlGes New Member

    I see... I have a diode in but it wont turn over every time I connect it. Weird... I'll try the idiot light route... where do I get one? Wire it myself? Thanks guys and thanks for the explanation/diagrams
     
  8. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Should already be one in your speedo cluster.
     
  9. CarlGes

    CarlGes New Member

    Would this most likely be the light that illuminates the "amp" light?
     
  10. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

  11. CarlGes

    CarlGes New Member

    If I hook that one up to the ign terminal the light stays on in the off position ( and still doesn't start)
     
  12. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    You should be able to remove the excite wire entirely and not affect starting and running.
     
  13. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    There's either something wrong with the wiring or there's a serious issue with the alternator- there should not be any juice at the ign terminal with the key off and the alternator should not be capable of putting voltage on terminal 1 when it isn't turning.

    Ignore the switch in the diagram below- - that's used on marine applications.

    [​IMG]
     
  14. CarlGes

    CarlGes New Member

    I got it... I'm just stupid... I think I might be good from here on out. But chances are I'll be back. I'm rewiring the whole jeep but an unexpected move (that's moving where I live) got thrown in, so I need the old girl to run at least to the new place where I can finish the wiring. Thanks again guys...
     
    jeepstar likes this.
  15. CarlGes

    CarlGes New Member

    Alright gents... so shes turning over but not firing up... had it started just 3 days ago... what am I missing?
     
  16. sterlclan

    sterlclan Member 2024 Sponsor 2022 Sponsor

    got juice to the coil in both run and start position? still have points? if yes on points they could be cooked with all the juice flowing without running
     
    ojgrsoi likes this.
  17. CarlGes

    CarlGes New Member

    Yup spot on... wire to the coil broke. Got it now thanks
     
    ojgrsoi likes this.
  18. CarlGes

    CarlGes New Member

    So I have a 15 amp fuse in line between the starter solenoid and the batt terminal on the alternator. I only used a 15 amp because that's what the PO had in before me but it has blown twice now. Do I increase the amp or do I have a problem elsewhere... I put in a fuse from a previous diagram... thanks in advance
     
  19. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    You'll need to check the part number of the alternator to verify it's output but the lowest they go is 35 amps; they will go full output when recharging the battery after starting.
    If yours turns out to be a higher output version you should consider upgrading the wire to a heavier gauge.

    A fuse is not stock, if actually equipped a fusible link would have been installed.
     
  20. Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    This for sure. It's not a good idea to run the alternator with no load (open circuit) if it is excited ( power to the 1&2 terms).