GM Inside - Muscle Cars - Jeep

Support FSC and see no ads! - Click Here
Results 1 to 8 of 8

New Alternator and still not charging

This is a discussion on New Alternator and still not charging within the Technical / Maintenance forums, part of the General Discussion category; I just bought a 1986 K30 with a 350 and 4 sp manual. It wasn't charging the battery so I ...

  1. #1
    Registered User
    Join Date
    Nov 2010
    Location
    Laramie, WY
    Posts
    3

    New Alternator and still not charging


    Support FSC and see no ads! - Click Here
    I just bought a 1986 K30 with a 350 and 4 sp manual. It wasn't charging the battery so I took the alternator out and got it tested. It failed so I bought a new one , put it in, and still no dice. As far as I know the battery is good too. Any ideas what else to check.

  2. #2
    EFI Live
    Join Date
    Jan 2008
    Location
    Wolfpack Country
    Posts
    10,285

    Re: New Alternator and still not charging

    you'll need a wiring diagram for the alternator to figure out which wire is suppose to be the hot wire. whenever the ignition is turned on it sends a signal to the alternator to tell it to turn on and charge. one you find which wire it is test it with a voltmeter and see if its getting power with the ignition on.

    “We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution.” -Abe

  3. #3
    Registered User dirtyhick42's Avatar
    Join Date
    Nov 2004
    Location
    Nacogdoches, TX
    Age
    24
    Posts
    1,320

    Re: New Alternator and still not charging

    Or maybe a bad belt tensioner causing the belt to slip around the alternator instead of spinning it like it is supposed to.
    Your name leads me to believe that you go to wyotech, can nobody there figure it out?

    2004 VW GTI VR6, DD status.
    2005 Silverado z71, black, leveled, 315s
    2000 k2500 OBS CCSB, 4x4, vortec 7.4, SAS with hp d44, 37s sold 4/3/11
    98 k1500 SOLD 6/8/10
    95 land rover discovery

  4. #4
    Registered User dave89iroc's Avatar
    Join Date
    Sep 2007
    Location
    SE Michigan
    Age
    36
    Posts
    4,812

    Re: New Alternator and still not charging

    big wire to the stud on the back of the alt should go strait to the batt, so, full time 12v, the red wire in the plug will also be 12v, might be key on only, and the small wire(usually brown) in the plug will be less then 12v key on, as it has the charge bulb in the circuit
    ASE Master Certified Technician

    2000 Silverado 6.0 4L80E 2wd
    *RIP*1994 Z71 SCLB 355, Dart Heads, 10.5:1 CR, PM rods, CC XR270HR

  5. #5
    Registered User
    Join Date
    Oct 2010
    Location
    north-central PA
    Posts
    743

    Re: New Alternator and still not charging

    You check the fusible link between alternator and battery? It probably blew due to over-voltage when your old alt crapped out. It's there to keep the battery from exploding, but I replaced mine with straight 2ga wire. *grin*

  6. #6
    Registered User
    Join Date
    Nov 2010
    Location
    Laramie, WY
    Posts
    3

    Re: New Alternator and still not charging

    Quote Originally Posted by dave89iroc View Post
    big wire to the stud on the back of the alt should go strait to the batt, so, full time 12v, the red wire in the plug will also be 12v, might be key on only, and the small wire(usually brown) in the plug will be less then 12v key on, as it has the charge bulb in the circuit
    So re-run the wire from the stud on the alt straight to the battery and leave the ones in the plug alone? I wasn't sure if there was a fusible link that I needed to keep intact or if doing that would cause another problem.


    I live in Laramie where Wyotech is, however I do not go there.

  7. #7
    Registered User dave89iroc's Avatar
    Join Date
    Sep 2007
    Location
    SE Michigan
    Age
    36
    Posts
    4,812

    Re: New Alternator and still not charging

    Quote Originally Posted by Go Wyo View Post
    So re-run the wire from the stud on the alt straight to the battery and leave the ones in the plug alone? I wasn't sure if there was a fusible link that I needed to keep intact or if doing that would cause another problem.


    I live in Laramie where Wyotech is, however I do not go there.
    did you test the wires?
    ASE Master Certified Technician

    2000 Silverado 6.0 4L80E 2wd
    *RIP*1994 Z71 SCLB 355, Dart Heads, 10.5:1 CR, PM rods, CC XR270HR

  8. #8
    Registered User
    Join Date
    Nov 2010
    Location
    Laramie, WY
    Posts
    3

    Re: New Alternator and still not charging

    Turns out i'm a complete idoit. I thought I had the belt tightened but apparently not enough. Tightened it and I'm good to go. Thanks for all the help and sorry about the waste of time.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •