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Hot Rods alternator help....car wont shut off

Discussion in 'The Hokey Ass Message Board' started by noclubjoe, Aug 7, 2011.

  1. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    so the volt gauge in my model a has been acting funny the last week or so, jumping around alot between 14-16 volts.... ok no problem ill just rebulid the alternator... fast foward to today. I take apart the alternator (stock chrome GM style internal reg.) to find the diode trio is burned up, Great! i install the new voltage regulator, diode trio, brushes, ohm the stator, clean up the commutator where the brushes ride, new bearings etc.... put her all together, runs good charging just over 14. Cool! go to shut it off..... still runs... ? i know about putting a diode in with the exciter wire to keep from feed back to the ign switch. ( had to do this on my OT Nova) my question is why now? i put this car together 6 years ago and never had this problem before? why with a rebulit alternator does this problem start? or could it be in the ing switch and it just shit today? what do you guys think?
     
  2. rustyangels
    Joined: Sep 28, 2010
    Posts: 170

    rustyangels
    Member

    Are you running an MSD box?
     
  3. markjenks
    Joined: Aug 31, 2009
    Posts: 383

    markjenks
    Member

    I'm guessing that the old regulator in the alt didn't need the diode and the new ones does. 5 mins fix after a trip to radio shack.
     
  4. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    no stock points ing system, i know what you mean about the MSD box, i run a digtal 6 box in my Nova and it did the same thing to me after i installed it. that i could understand because the car had never ran with a msd system before.
     
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  5. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    oh by the way guys i forgot to add in my first post.... after the car not shutting down with the chrome alternator that i was in, i put on a stock GM alternator that i had laying around just to try it...... same shit wont shut down....? Mark i see what your saying about the new regulator not needing the diode, but with 2 different alternators and still the same problem?
     
  6. rustyangels
    Joined: Sep 28, 2010
    Posts: 170

    rustyangels
    Member

    Any other hot wires feeding off the positive+ terminal on the coil?
     
  7. wildearp
    Joined: Oct 24, 2007
    Posts: 520

    wildearp
    ALLIANCE MEMBER
    from tucson, az

    If you have an accessory side on your ignition switch, if you tie the exciter to that side and the ignition to the ignition side, they will separate when power is off and you won't need a diode.
     
  8. Weasel
    Joined: Dec 30, 2007
    Posts: 6,720

    Weasel
    Member

    There is a little known condition with GM alternators where they are prone to backfeeding despite all electrics being switched off - cost me a lot of money finding this out the hard way. Painless Wiring has a kit for around $85.00 to eliminate this problem....
     
  9. ironpile
    Joined: Jul 3, 2005
    Posts: 915

    ironpile
    Member

    Alt and ign hooked to same hot wire
     
  10. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    thanks for the info guys, iam sure i will get this taken care of later today when i get out of work, my question is still why has this car been fine and shut off for the last 6 yrs? only when i changed the parts in the alt. with new parts has this problem came up? i dont have a problem doing any of the above to slove it...it just really seems odd that it has been fine up untill now?
     
  11. porknbeaner
    Joined: Sep 12, 2003
    Posts: 25,737

    porknbeaner
    Member

    All power to your dizzy should go through the ignition switch with the exception of the hot start wire that comes from your starter solenoid. You should not be getting any hot directly from the alternator to the ignition. if you are you have it wired wrong.

    First thing I would try is this; if you have a hot start wire from the solenoid to the coil, shut the switch off and then pull the hot start wire from the solenoid. If that kills it I would suspect the starter solenoid. If it still doesn't shut off I would suspect the ignition switch.
     
  12. 26 roadster
    Joined: Apr 21, 2008
    Posts: 1,823

    26 roadster
    Member

    I think any electrical part that has small colored parts in it is FM, (FREEK'IN MAGIC) and I don't argue with it, put in the diode!
    Lights will go bad setting on the shelf I have found
    fuses that LOOK good, are not
    the list goes on.............................
     
  13. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    Guys i think everyone is missing my question......... i dont have a problem putting in the diode if thats what needs to be done, what i want to know is why does it need it now? this car has been shutting off with the key for 6 years with out a diode in the wire!
     
  14. George/Maine
    Joined: Jan 6, 2011
    Posts: 956

    George/Maine
    Member

    If you have a regulator and has I wire thats goes to IGN switch,my guess its the reg thats at fault.
     
  15. ironpile
    Joined: Jul 3, 2005
    Posts: 915

    ironpile
    Member

    I Remember now,one of the bolts in the diode trio is the wrong one and is grounding it full time,ck the bolts and you should be fit to go. All three should have a plastic washer on them.
     
  16. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    ok thanks this was the kind of answer i was looking for, when i took it apart only 2 had the plastic washer around them, so i put it back together that way........ maybe this is the reason that the old diode trio was burnt to a crisp, and the volt gauge was jumping around all over the place....??? iam going to take the alternator back apart and double check everything... thanks guys!
     
  17. snowmann
    Joined: Feb 16, 2009
    Posts: 98

    snowmann
    Member
    from Sabin MN

    I have the exact same problem, when my chromey alt went out, got to go to radio shack to get a diode. Anyone have a part #? My local radio shack is lacking a little knowledge in that department. Thanks.
     
  18. jackandeuces
    Joined: Feb 20, 2006
    Posts: 823

    jackandeuces
    Member

    Broad question without knowing how the alternator is wired ....
     
  19. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    doesnt matter any more the problem is fixed
     
  20. jackandeuces
    Joined: Feb 20, 2006
    Posts: 823

    jackandeuces
    Member

    What was the fix...
     
  21. snowmann
    Joined: Feb 16, 2009
    Posts: 98

    snowmann
    Member
    from Sabin MN

    Anyone? Still havent fixed this.
     
  22. noclubjoe
    Joined: Aug 24, 2005
    Posts: 626

    noclubjoe
    Member

    how is your alt wired? mine was...the exciter wire was to #1 on the plug and #2 looped over to the battery lug it worked fine this way for 6 years, untill i replaced the parts, talking to a friend that rebuilds alternators, generators, starters etc.... he told me that some of the replacement parts they sell require the #1 and #2 to be switched....dont ask me why?? he went into why they have to be switched but i didnt get what he was talking about. anyway, i did this and the car shuts off with the key and charges just fine...... try this it may work....
     

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