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Alternator Issue

Discussion in 'Early CJ5 and CJ6 Tech' started by Steve's 70-5, Oct 21, 2021.

  1. Oct 25, 2021
    Sierra Bum

    Sierra Bum Member

    The High Sierra
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    The smaller red wire you have connected to the charge stud...where does that come from? You probably don't need it.
     
  2. Oct 25, 2021
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    If you have an alligator clip or a short length of wire & and the proper terminals connect the alternator stud to terminal "2", then start it up & check the voltage.
     
  3. Oct 25, 2021
    Sierra Bum

    Sierra Bum Member

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    This is the typical Delco connector: HERE.

    As Howard suggested, Terminal 2 is the lower one in the pic. Connect a wire from there to the charge stud. Try that.
     
  4. Oct 25, 2021
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    Doing some googling. One wire alternators are not that common on vehicles, mostly used on equipment. Found one at NAPA, 2134011SW (SW is for single wire).
     
  5. Oct 25, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Yes - looks like a 3 wire...you'll need the jumper wire from the blade terminal to the BATT post....
    check this out...the 12si stuff is down a bit below the 10si info:
    Catalog

    here is a decent figure....the white wire sierra bum mentions to cap off is the one that goes to the indicator light (and that I think you were trying to use for the voltmeter?)...you could just leave that blade terminal empty.
    [​IMG]
     
    dnb71R2 likes this.
  6. Oct 25, 2021
    Sierra Bum

    Sierra Bum Member

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    Fino Beat me to it haha... .Not my picture. I stole it off the interwebs. Disregard the green (white wire usually) Its this easy:
    [​IMG]
     
  7. Oct 25, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
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    I have shared this image several times, because I believe it is the right solution for our old Jeeps and most modified applications.
    It has worked well for me (FORGET the 1 wire thing!). Even if you don't want the idiot light, just skip that part of the circuit (connection #1 at the alternator).
    This is the 4-wire alternator set-up; it's is the commonly referred to 3-wire connection with an additional ground from the alternator to the battery. Realize that getting a good ground through the motor mounts may not be a good plan.
    It's really not that tough to connect. Good luck.

    [​IMG]
     
    FlatlanderCJ5 and Sierra Bum like this.
  8. Oct 25, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    The modular alternators like 10SI and 12SI ("systems integrated") are easy to work on. Just replace the regulator with the part I linked to make a one wire, if that's what you want. You'll need a toothpick to hold back the brushes when you put the case halves together.
     
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  9. Oct 25, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

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    AND, if you want to re-clock the alternator case for something more suitable to your application, you can rotate the back half in 4 different positions relative to front half. This makes the 10SI & 12SI cases very friendly to varied applications.
    In my case, I order a 1985 Buick Riviera alternator (94 amp 12SI unit) and I re-clock the case 90 degrees for an optimum fit in my CJ.
     
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  10. Oct 25, 2021
    Sierra Bum

    Sierra Bum Member

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    dnb5853....the above diagram, that's a smart way to do it. Close to how I wired mine. And I like the ground wire off the alt. There's other versions, but that is certainly a good one.

    And I too agree on forgetting the 1 wire deal.
     
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  11. Oct 25, 2021
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    I am having the front end aligned this weekend, do not want to get stranded to or from the shop. Want to get the front end done so I can drive it. At this time I do not want to get back in the dash and run the excite wire. Will have winter time to fool with this. Will get the one wire, get the jeep running and go from there
     
    Fireball likes this.
  12. Oct 26, 2021
    amboynut

    amboynut Member

    Chelatchie, WA
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    Alternators don't care which direction they spin, but the fan built into the pulley does.
    When adding the factory AC kit to early Honda Civics the alternator was remounted to spin the opposite direction, but the kit included a pulley with a "backwards" fan.
     
  13. Oct 26, 2021
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
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    I am a happy camper, Jeep alternator is charging. This is the first time I have driven the Jeep on a short drive and voltage reading at the battery was higher than when I started out.

    [​IMG]

    [​IMG]


    Was thinking.

    Let me say this, I do not want to pull the ignition switch or cluster

    If I was to use the 3 wire alternator I have, can I pull/tap into the wire at the starter. When you start the Jeep this excite the alternator, so when turning key it engages the starter solenoid. I do not have a idiot light in my cluster. Am I hopping for the best

    Let me say again, I do not want to pull the ignition switch or cluster
     
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  14. Oct 26, 2021
    Uncle Vin

    Uncle Vin Member 2022 Sponsor

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    This article is a great read on one-wire vs. three-wire alternators. It's worth a look: Catalog
     
  15. Oct 26, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Yes, I have heard of doing this before. On a Ford-type solenoid, there is a small post labeled "I" that energizes when the starter is running. Should be a similar post on a Delco-type solenoid, or you could use the large starter post. (y)
     
  16. Oct 26, 2021
    Sierra Bum

    Sierra Bum Member

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    Did you solve this with the "simple method" above.

    If I understand you correctly, you would like to have an in-dash charge warning light, and are trying to avoid pulling out the ignition switch? Do you have an in-dash volt meter? This is great for monitoring current while driving. If you do not have one, I'd suggest investing in it. A volt meter is quite useful and easy to hook-up. Although, you will need a wire coming somewhere off the ignition or ACC pole of the ignition switch.

    To respond to your question about splicing into your harness....it depends how your ignition circuit is wired. Personally, I would not splice into anything unless you know what your doing and where things go. Tim had a good explanation early on for wiring the excite wire / warning light connection. It connects to the ignition side of the side of the switch as well. See below:

    Think of it this way....There is a wire (terminal 1 on ALT) going from the alternator to the ignition switch (ignition pole of switch), and it has a little light bulb in middle of the circuit. Engine OFF and key ON the bulb illuminates because it has a ground- from the Alt and positive current+ from the ignition switch. So you start the engine, the alternator starts to produce current and the light goes out because it looses its ground. This tells you the alternator is producing current and working.

    The thing is, an alternator can produce enough to "turn off" the warning light, but still be underperforming or failing. This is why a Voltmeter is useful. Not to mention it will give you a battery reading when the engine is off and key in "on" position.
     
  17. Oct 26, 2021
    Sierra Bum

    Sierra Bum Member

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    Basically the excite wire (terminal 1 on ALT in above diagram) is not required for the ALT to function. You only need the sense wire (terminal 2 on ALT) connected.
     
  18. Oct 26, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Recall that the alternator uses part of the current it generates to energize the field windings. The more current fed back, the stronger the magnetic field and the more current the alternator makes. Indeed, this is how the alternator regulates the battery voltage. More or less self-generated current is fed back to the alternator windings, creating more or less output current which raises or lowers the charging voltage. Normally the excite wire current is used to bootstrap this process, allowing the output current to start to flow.

    Well ... some claim that, if you spin the alternator fast enough, the residual magnetism in the iron of the alternator core will cause the alternator to start self-generating. There's no rule for how fast the alternator has to spin, or if it's actually going to start up. You pretty much need the excite wire. The one-wire circuit can bootstrap itself, but it's an added circuit.
     
    Last edited: Oct 26, 2021
  19. Oct 28, 2021
    truckee4x4

    truckee4x4 Grant Kaye 2023 Sponsor 2022 Sponsor

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    Steve , not sure if it helps you, but I am running a Powermaster 8-46101 (https://www.summitracing.com/parts/pwm-8-46101). The two wires on the one post go to the battery (+) and to the Fuse block under the dash.
    UNADJUSTEDNONRAW_thumb_82cf.jpg

    UNADJUSTEDNONRAW_thumb_82c8.jpg

    I need to get a spacer on the pulley to correct the alignment with the pulley on the water pump as it is shorter than the OEM alternator.
     
  20. Nov 2, 2021
    Walt Couch

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

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    This is true. Altho after long sitting spells the rotor will loose the residual magnetism and will refuse to self generate. If you full field the alternator it will start charging again and restore the magnetism to the rotor. Full field tab of the internal regulator is shown below (red arrow). Note not all Delco alt have this test half moon hole.
    [​IMG]
     
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