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Motorola Exciter Wire

Discussion in 'Intermediate CJ-5/6/7/8' started by David Littleton, Nov 12, 2019.

  1. Nov 12, 2019
    David Littleton

    David Littleton New Member

    St Louis MO
    Joined:
    Jan 21, 2018
    Messages:
    13
    My 74 has a Motorola alt system, the PO installed a electronic distributor and had the exciter wire running off the " I" terminal of the starter solenoid . The alternator will not charge until I jump from the hot + lead to the white wire then it will charge to 13-14 volts until I turn it off then restart, then no charge. from what I see on the wiring diagram the exciter wire is tied in to a continually 12volt source with the Key On Run position. The "I" terminal is only hot during the start cycle. which I think is not enough time to excite the alternator'? Am I reading the diagram correctly?
     
  2. Nov 12, 2019
    sterlclan

    sterlclan Member Sponsor

    exploring the...
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    Yes the exited wire needs switched power
     
  3. Nov 12, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    Oct 6, 2003
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    Best thing you can do is replace the Motorola. Mine would die if it got wet. Left me stranded a few times crossing creeks etc.. I installed a CSI 120 in mine and got rid of the voltage regulator that kept going out.. The CSI 120 is internally regulated. And has a much higher output. I used to carry a spare regulator.. Might still have it on a shelf someplace.
     
  4. Nov 12, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

    Medford Mass USA
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    The Delco alternators (10CSI, 12CSI) are cheap, more reliable than the Motorola alternators, repair parts are available, and simple to connect. The Motorolas were popping diodes back in the day ... the Jeep shop mechanics would take them apart, solder in new diodes, and that was a repair. Maybe their components are better today, but I expect you have to take whatever the reman shops give you if it breaks down.

    Don't use a whomping powerful alternator with your factory ammeter, if present. Note the Delcos typically come with a much higher charge rating (ie 70A or 100A vs original 35A) so be aware. You can convert to a voltmeter rather easily, which allows the higher charge current to go directly to the battery.
     
    zila likes this.
  5. Nov 12, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    Mine has a volt meter..
     
  6. Nov 13, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

    Medford Mass USA
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    '74 was the last year for the ammeter, and it was optional (the "gauge package" with an oil pressure gauge).
     
  7. Nov 13, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
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    53
    re: 10CSI / 12CSI swap

    Are the housing bolt patterns the same, or will the stock "motorola" bracket require fabrication? (or do you get a 10/12CSI bracket? )
     
  8. Nov 13, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    I had to make one small adjustment. There is a piece attaching the alt to the block. I measured the difference old/new and cut off that much and rethreaded. The other part was fine and lined the belt up. I also rewired it and lost the OEM volt reg. Lots of info on the interweb on how to connect. I got a plug that goes into the alternator socket at NAPA. Can't remember all the details but it was fairly easy to wire.

    My engine is a 304
     
    Last edited: Nov 13, 2019
  9. Nov 14, 2019
    obarrett

    obarrett Member

    Lake County, CA
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    Sep 8, 2010
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    thx zila...
     
  10. Nov 14, 2019
    David Littleton

    David Littleton New Member

    St Louis MO
    Joined:
    Jan 21, 2018
    Messages:
    13
    thanks for the answers and advise ,I can get it to work with a jumper wire so if I repair this issue I will have a charging system and if it fails I will go the Delco route. thanks again
     

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