ammeter question

1

1929tudor

Senior Member
When i start my car the ammeter reads on the postive side when idling and looks good. As soon as I take off, the needle gets buried on the discharge side and won't even move. yellow wire on discharge and y/b on charge side. I'm running an alternator if that makes any difference. What would cause that? Thanks
 
Last edited:
If it is a negative ground alternator, the amp leads need to be reversed, as Tom said. A's originally were positive ground.
 
1929tudor said:
When i start my car the ammeter reads on the postive side when idling and looks good. As soon as I take off, the needle gets buried on the discharge side and won't even move. yellow wire on discharge and y/b on charge side. I'm running an alternator if that makes any difference. What would cause that? Thanks
Click to expand...

I agree the wiring to ammeter is reversed. What currently looks like a good charging rate on start up, is actually the discharge required to run the ignition system before the alternator kicks in. Once you rev the engine to drive away, the alternator wakes up and tries to recharge you somewhat depleted battery. That will momentarily at least peg the needle of even a 30 amp gauge. Mine sticks in the pegged state until I give a little tap on the glass.

Steve
 
Thanks Steve for your suggestion. All that responded, Thank you very much. It's great to get help when you don't know that much like me. I greatly appreciate it.
 
You must log in or register to reply here.
Back
Top