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Troubleshooting 140amp alternator upgrade

Discussion in 'The Garage' started by RootBreaker, Apr 26, 2005.

  1. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    forgive me for I do not know much about the charging systems on auto's :(

    Ok so I have had a 140 amp alternator for a few months now... bought the wire adapter from advanced auto parts. Tonight.. I installed it... was a close fit so it went in with a lil persuasion :grin:
    now I hooked up the wire that goes to the back of the alt on the stem (battery I think)
    Then here is where it gets a little bit tricky but not much... I was told on the newer alts... black is ground, red is power and brown is idiot light or gauge...
    Thus I cut my plug off and put red to red and black to black. I did not hook up the brown wire....

    so jump the truck as it is dead..... let it run for a bit....
    take jumper cables off and truck stays running.... but interrior light drops down low... then turn on kc's to really suck the juice and the truck shuts off... dead battery.....

    did I do something wrong on the 140amp upgrade?

    I took the alt out and ran to autozone and they tested it and it passed on the machine.....

    please help SOMEONE as I wish to finish this lil project... .if it wasnt for bad luck I would have none at all!!!!!
    :crazy:
    Jeff
     
  2. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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  3. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    Thanks... read it and I did all of that... however I used a different plug... pm'd ya...
     
  4. mouse

    mouse 1/2 ton status

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    I just picked up a conversion cable last week from the dealership and plan this mod as well. Please let us know what your problem is. Also, how about a pic of the bracket mod?

    Best of luck!
     
  5. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    my bracket mod was easy... cut about 1/4" off the bottom bracket... but cut too much so put some washers on behind it... and it lined up with the top when I applied a little bit of force.... will snap a pic tomorrow...

    Well I already cut my wires but could buy the other adapter..but do not see why I would need that....

    hey can you post a pic of your adapter? is the red to red and black to black?/ no connection to the third wire???
     
  6. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    reading the link from mrk5 I realize that what he says in bold.. is if you do not have the idiot light.. you need the resistor wire set... maybe I will just order that tomorrow.... and give that a try.... if it works then I am glad....
     
  7. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    mrk5's info is from here
    http://www.novaresource.org/alternator.htm
    pics are not easy to see but you see it looks like a normal alt.... :grin:
     
  8. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    last stupid question and Im going to bed....
    I need to measure the resistance of the wire and see if I have 35 ohms... what wire do I measure and from where to where?
    boy I dont know anything about this subject.. was never good with car electrical... but got my relays for kc's right :grin:
     
  9. az-k5

    az-k5 1/2 ton status

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    Use that idiot light system. I had this same problem. It fixed it just fine. As for the 35 ohm's I used a side marker light (had it laying around) and that was perfect. Never put a guage on it but haven't had a problem.
     
  10. 79Jimmy

    79Jimmy 1/2 ton status

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    Try this....

    http://coloradok5.com/forums/showthread.php?t=105791

    I didn't need any resistors or bulbs. I made my own adapter harness by splicing a modified (cut two of the wires off :) )CS harness to a two wire harness that fit my '79 SI alternator. I can swap in an old style SI alternator any time(great trail spare) :cool1: Red ("S" on the CS harness) to red and brown ("L" on the CS harness) to brown and the main battery cable bolts on the back. "F" and "P" on the CS harness are not used. I've got a volt gauge in my '79 and this setup has worked flawlessly for a couple of years now :cool1:

    James
     
    Last edited: Apr 26, 2005
  11. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    so I have the red to red and black to black on my new cs harness.. you say just tie the brown wire in with the red wire?? wont hurt anything??
    Thanks
    Jeff
     
  12. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    I called autozone and advance auto and they cannot help...
    called a chevy dealer... and they were clueless also...

    can anyone help?

    can I just goto radioshack and get a 35ohm resister and tie one end of it to the brown wire and the other end to the battery (or ignition)?
     
  13. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    sorry to beat this so much.. but it is driving me crazy!!!!!

    so looking at this pic...

    1. just take the brown wire and run it into the cab
    2. connect it to a dash light (as I have spares)
    3. other side to battery in fuse block
    ??????????????????????????????????????????????????????????????????

    just noticed....
    one wire goes from the alt plug to the light
    the other goes to the battery

    so now I am really confused...
    I have 3 wires..... red = battery? black = ground? brown small wire goes to lamp????

    [​IMG]
     
    Last edited: Apr 27, 2005
  14. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    well I found their website... acdelco
    DUHHH
    http://www.acdelco.com

    put in my zip and it told me a place down the road.. calling them now...
    will see if they can get it....
    :crazy:

    WOOOHOOOO THEY ORDERED IT AND WILL HAVE IT BY 3pm... $25 plus nj 6%
    I frankly didnt care if it is $50 at this point...

    the only problem I have is I cut my old plug off... and dont think I left alot of room!!!!
     
  15. 79Jimmy

    79Jimmy 1/2 ton status

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    No. There should only be 3 wires total that are connected to the alternator.
    1) The main red battery cable which bolts onto the back of the alternator

    and looking at your diagram the other 2 which plug into the side. Of these 2, #2 is red and a heavier gauge and is +12VDC it connects to the "S" wire on the CS harness which should also be red and a heavier guage. #1 should be brown and a lesser guage than the other red one. It connects to the "L" wire on the CS harness which should also be brown on the CS harness. There is no "ground" wire, the alternator case is grounded when you mount it.

    Hope that helps

    James
     
  16. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    hmmmm the wire plug I bought from advanced auto is this one... well looks close to it.. although the wires are not colored in this pic...
    [​IMG]


    big red wire I put on my old red
    big black I put on my old black
    Left small brown alone

    so if there is no ground.. should I have put the small brown wire to the old black one???
     
  17. az-k5

    az-k5 1/2 ton status

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    The plug on the pontiac 140A alt has a computer wire on it. I think it was the brown on you won't need.
     
  18. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    well think I gotit.... went and picked up the wire adapter.... from a local shop.. $23 guess not bad... had to re-splice my old pigtail back on... I did not leave alot when I cut it as I had just enough room to put the crimps on... but plugged it all together and think it is working.. will find out later.. not in the mood at the moment as I have a few other things going on at this moment....
    Thanks for all the help...
    is greatly appreciated...
    Jeff
     
  19. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    That sounds like about how much I paid for mine. Hope it works for you.
     
  20. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    well I went out and ran the truck for a while.. turned kc's and hi beams on.... no go no luck... no recharging!!!!! dunno why... this sucks...

    how can I troubleshoot this?
    I bought the acdelco 8078 and that didnt work... also bought the other plug... maybe I dont need the ac delco plug... I did notice that the new wire plug.. had only 2 wires.. maybe I should try that first... try using my meter to figure out which ones they are using and hook those 2 up... I didnt hook up the small brown.. but maybe I need to use the red and brown???

    im debating on just going and buying the right one for my truck and screw the upgrade.... :crazy:
     

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