gm alternator swap

Discussion in 'Engine/Drivetrain' started by rphamil, Mar 28, 2011.

  1. rphamil

    rphamil Newbie

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    I have a 79 hilux. When i got it from my dad it had the gm alternator on it. Well the bracket broke and i broke the ear off the alternator trying to fix it so i changed the alternator out. Drove it home ran fine went out next mourning and nothing. My dad said the polarity must be reversed i dont know just wanna figure this out so i dont have to go back to hilux alternator
     
  2. White Trash

    White Trash Toyotaholic

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    Sounds like the field stayed energized and drained the battery. The smaller wire coming out of the side plug should be switched power with the key. If it is constant you found your issue.
     
  3. rphamil

    rphamil Newbie

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    I dont know alot about wiring really nothing. I put the gm wire harness on it and i have a wire from the battery and i hooked them together at rhe threaded post on the alternator
     
  4. rphamil

    rphamil Newbie

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    That fixed it. I think find out in bit after i let it sit for a while
     
  5. jackash002

    jackash002 Enthusiast

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    inside the alternator there is an electromagnet switch and if you have that hooked up to power it stays energized(on) and wears down the batt. just like a dome light. i had that issue when swapping on my 83.( had it hooked to the wrong wire, which made the truck stay on by keeping the on wire powered, seemed wierd at the time.. i think the right wire had a resistor or something that preventing back-powering the ign. switch..?) if you have the one wire you just hook to battery, done.. if you have the 3 wire, you have to wire it correctly, although they make a conversion kit for it as well, dont know much about that, and you can wire it as a one wire somehow... lot of hot rodders do it for clean/simple engine bay.

    i have some pics a lil past half way under BAWright that i thought were pretty good on the install

    22RE alternator upgrade - Pirate4x4.Com Bulletin Board
     
  6. planemos

    planemos Toyotaholic

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    I bought a LCEngineering high output alt which is a gm style. There is a plug on the back of it and it is filled with clear silicon. And then there is a post to attach to on the side and it is a 1 wire. The probably do a conversion I would guess. I don't really know the details but yea it is just hook up one wire the the battery and done. so I guess the body of the alt is grounded throught the mounting bracket or something...?
     
  7. rphamil

    rphamil Newbie

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    The way i have mine i think would be consided one wire. I did not use the original harness at all. The alternator i have is off a 85 model chevy 65 amp. I bought the gm pigtail that goes in it and crimped on ring terminals and put them on the threaded post then from there a wire to battery. I went out this morning thinking i fixed it but again nothing, so im gonna take my battery to work to test and charge it because it may be bad not sure but i kinda hope thats what it is
     
  8. TRUCK ACTION

    TRUCK ACTION Grand Toyotaholic

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  9. White Trash

    White Trash Toyotaholic

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    If you put ring terminals on BOTH wires coming off the side plug thats your issue. The field is staying energized and draining your battery. Only the larger of the 2 wires should be connected to the charge stud.
     
  10. rphamil

    rphamil Newbie

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    Both wires are the same size and originally they were both hooked up. And if im suppose to leave one off where does it hook up. The original toyota wiring harness for the alternator is off to the side im not using it at all. The original harness i see a small wire but not how mine is wired
     
  11. White Trash

    White Trash Toyotaholic

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    As viewed from the back of the alternator the right wire goes to the chatge stud and the left can either be wired to a switched power source or clipped off. If clipped the alternator will start charging at roughly 1200 rpm.
     
  12. rphamil

    rphamil Newbie

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    Thanks for the advice ill try it when i get home from work
     
  13. rphamil

    rphamil Newbie

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    Ok so i charged and tested the battery its good. I cut the wire and capped it off and just clicks so i jump started it and it fired right up turned it off after it ran for a while turned it off and nothing again. Starting to get mad cant figure it out is this gonna be easier with a one wire gm alternator
     

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