Can’t get an alternator to put out a charge

Electrical & Ignition

  1. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    I just connected the two wires to the voltage regulator directly together and finally got a charge. I haven’t tried that yet so now I am rummaging through my inventory for A voltage regulator.
     
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  2. 70NEWYORKER

    70NEWYORKER Well-Known Member

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    That interpretation never occurred to me before.... :rofl:
     
  3. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Replace the voltage regulator and all is good!:)
    Thanks for the help you guys I appreciate it big time!:thankyou:
     
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  4. traintech55

    traintech55 Senior Member

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    Not the first time a bad alternator took out a regulator.
     
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  5. 62dodge

    62dodge Active Member

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    Howdy Last time that I fought a charging issue the regulator and alternator were taking each other out I had to replace both at once. That's after trying three alts. and two regulators. The car was a 65 Dodge
     
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  6. furious70

    furious70 Well-Known Member

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    Glad you found it. I do second the wire break as an odd ball thing that does happen. Happened to my 72 RR 3 years back. I was scratching my head until I started poking the field wire with my tester probe...had power about half way to the alt and then nothing.
     
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  7. Gerald Morris

    Gerald Morris Senior Member

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    That was going to be MY suggestion.
     
  8. saylor

    saylor Senior Member

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    dug up this thread - fighting low alternator output. battery is on charger now i tapped it out again . . .

    changed to a FURYGT voltage regulator from stock. didnt help. wired 2x50A circuits from ALT+ to BATT+. didnt help. added ground strap from engine block to frame. didnt help. added ground strap from ALT body to firewall. didnt help.
    changed ALT with old one known good off old 383. didnt help.

    have 11.9 at idle up to 12.~ at r.p.m.
    have 11.9v at blue wire at ballast resistor with key in RUN engine OFF.
    .02v ~ across ALT case to frame.
    .02v ~ across BATT- to voltage regualtor housing.

    have not grounded ALT FLD to ground what do i do just throw alligator clips on it to ground?

    looking at this old ass wiring - could a guy just run new wire from ALT FLD to VR FLD and another new wire from IGN SW to ballast resistor+ IGN (my existing wire is forked to both spots) on voltage regulator?


    I removed the A/C compressor on an A/C car so trying to rhubarb up the belt paths... i have ALT and P/S driving off the same crank pulley #2 pulley with a 61" belt.

    how would i tell if i have the ALT spinning enough? like compared to the stock belt path? does more belt contact / wrap / angle around the pulley = more turn? or as long as the belt touches it turns at whatever the main crank is doing? see pic its decently engaged IMO.

    trying to charge -

    - saylor
    20191128_073558.jpg
     
  9. furious70

    furious70 Well-Known Member

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    For the simple question, you should have plenty of rpm to get a full charge going. If it was slipping it'd be squealing
     
  10. saylor

    saylor Senior Member

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    right thanks for the reply. i agree its not slipping.
    what i meant was/is - think of the vbelt around the pulley like a 'C' shape. then think of the vbelt around the pulley like a 'U' shape. would the 'U' shape turn the pulley any faster than the 'C' shape, as more belt is engaged with the 'U' shape to pulley comapred to the 'C' shape to pulley?
     
  11. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    Early (one field connection) or late (two field connections)? From what you are saying about the FuryGT VR, I'd say it's the early version, but let's be sure.

    If it's an early version, unclip the field wire and jumper from alternator field connection to the output post on the alternator, not to ground. Turn on your headlights and start the car. Check voltage at the battery.

    The later versions use ground to turn the field in the alternator off and on. Earlier version use +power to do the job.
     
  12. saylor

    saylor Senior Member

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    Mr. Big John its early style with 1 field connection and 1 hot post.

    forgive me for being slow here, but i read a post where a guy fried his hand and his alt so im trying not to die. and a lot of posts out there talk about both styles alternator early and later model at the same time and get confusing, or show a diagram for the 2 field ALT but talk about 1 field, etc., etc.

    you are saying:
    unclip field terminal wire from its blade on ALT. leave wire dangling.
    take piece wire and go from that field terminal blade on ALT to BATT+ post on ALT?
    turn on headlights (!) and start the car.
    check voltage at battery.
    try not to die.
    come back here and tell Mr. Big John results.

    what should i expect when i check voltage at the moment of test?

    Thanks!

    - saylor
     
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  13. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    13.2+ volts if the alternator is charging. The '70 SFGT regulator won't work with the single field terminal setup as it provides a ground and there will be no juice to the field to initiate charging. (SFGT used 2 terminal field setup. or did you mean you bought one from that member?)) Usually works best to hook the hot lead to the + terminal on the battery.What year car are you working on? '70 and later Mopars used the two lead field setup with an electronic regulator. Most older ones were the single wire type.

    Dave
     
    Last edited: Dec 8, 2019
  14. 78Brougham

    78Brougham Deplorable FCBO Gold Member

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    14.2- +/-
    Just for the hell of it, check the connections on the ammeter gauge at the back of the instrument cluster. They can cause some funky problems.
     
  15. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    More likely, if all is working right, you'll see 14 or more volts. That is why you want to turn on the lights to add a load. Don't run it long as it's not good for the battery.
     
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  16. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    Yea, we're talking about the electronic regulator that (member) @FURYGT sells.
     
  17. saylor

    saylor Senior Member

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    thanks but bypassed/removed MAD-nacho style and have elcheapo volt meter now. there is a wire join back there tho tbh. . .

    yes sorry for the confusion. Mr. big john and i can relate we are on the same page. i meant the upgraded VR from member FURYGT - who is 100% awesome to deal with btw

    I have the battery on 2amp charge right now/ overnight, and usually dont get time during the week to goof with the car, so it may be whenever before i can test and report back, but its next thing in line the car aint movin til this is worked out.

    thanks all!

    - saylor
     
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  18. saylor

    saylor Senior Member

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    so i got out there today and if i held the RPM at ~2000 my voltage gauge would go from 12v to 14v in a slow repeating pattern. idle it goes under 12.
    i took a jumper wire alligator clips from FLD to BATT post on alternator, turned on lights, started car. no change at all.

    whats next, carry these alternators up to vatozone and have them test them?
     
  19. furious70

    furious70 Well-Known Member

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    So if you hold it at 2000rpm the voltage occilates 12 to 14 on a good gauge?
     
  20. saylor

    saylor Senior Member

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    yes if i hold the RPM up the gauge would climb from 12 to 14 and fall back to12.

    at idle it dips below 12. but like i drove around the neighborhood, i never got above 1500rpm really, so i have to improve this somehow.