Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Alternator voltage at idle

Discussion in 'The Garage' started by reverett, Jul 31, 2006.

  1. reverett

    reverett Registered Member

    Joined:
    Mar 25, 2006
    Posts:
    11
    Likes Received:
    0
    Location:
    Seattle, WA
    Ok, I have an 84 K5, relatively stock to my knowledge. After doing some research and searches on this site I tried the recommendations of testing the charging system with a multimeter, here's my results followed by a question or two...

    Motor off, voltage at Battery 12.60 (OK)
    Motor running fast idle 14.30V (OK)
    Motor running fast idle, everything on 14.30V
    Motor running reg idle 500-600 rpm, everything on 12.60V
    Motor running reg idle 500-600 rpm, I turn everything off 12.60V

    So I run around to the cab and give it a little gas...
    Motor running reg idle 500-600 rpm, everything off 14.30 V
    and it stays there until I turn everything on then it drops...

    So my question is, is this normal? Or is something wrong and if it's wrong is it my voltage reg inside the alternator? Or would a higher amp alternator help when at idle?


    BTW... for those who probably freeked out when you saw your in dash voltmeter drop to what you think is 8 volts, mine was there but the multimeter read 12.60 V.

    Thanks!
    Rob...
     
  2. neverendingproject

    neverendingproject 1/2 ton status

    Joined:
    Jul 24, 2005
    Posts:
    1,637
    Likes Received:
    0
    Location:
    Tulsa, OK
    You need to set your idle a little higher. The alternator wont kick in till 750 rpm or so.
     
  3. Dallin

    Dallin 1/2 ton status

    Joined:
    Feb 12, 2003
    Posts:
    135
    Likes Received:
    0
    Your results aren't that unusual. I'm guessing your alternator is a 10si. Upgrading to a CS140 would probably keep your voltage up at idle. There are plenty of posts on how to do it.
     
  4. chevyryan

    chevyryan Registered Member

    Joined:
    Aug 1, 2006
    Posts:
    13
    Likes Received:
    0
    Location:
    colorado
    well if its a 350 you definately need to set the idle higher, that might help
     

Share This Page