Alt not charging

The amp gauge should jump around (flips from slightly negative to several amps positive couple times a second).

There isn't an obvious fix that I know of, but I might double check all the wiring to make sure something didn't come loose.

The past two drives have been the same: it shows a slight discharge for about ten minutes and then jumps to about half way in the positive. It is no longer jumping around - it stays pretty solid.

I don't understand why it is discharging until I have been driving for a while.

Nick, thanks for the input. If no one has seen a problem problem like this I will take it to the shop and have them trace all the wires.

Robert

Did you change the regulator also?

Didn't think to pull the regulator when I pulled the alternator. The regulator was my next guess, but the problem of delayed charging seemed unique enough to ask about.

I will change the regulator. Might as well, they are super cheap.

Robert

My GM one wire alternator does not start charging until I reach about 1500 rpm. Maybe your alternator works the same way but at a higher rpm?

Art

The guage doesn't show charging at any RPM for several minutes. Then it shows a charge even at idle.

Robert

...not changing the External Voltage regulator at the same time as the 'New' Alternator was a mistake!! That regulator Might be the reason the previous Alternator went out; and now it may well be the reason Your New Alternator went out! Alternators with External Regulators Must Always be replaced as a set. When You go to a New Alternator, You should 'Step-Up' to a 'Built-In' regulator. Still better, are the Alternators that have the Internal cooling fan...

I had a very similar problem.

I changed the alternator and regulator and that cured it. I went through the wiring schematics and it is generally caused by a short in the alternator that causes an open short (diode) in the regulator or vis versa.

HTH

Bohdan

It may not be the regulator. I have had problems with the connector on the regulator. Some times you can take it off, crimp the connectors tighter, and put it back on. Then things work fine. It is also advisable to add a little grease to the connector to prevent rust of the connection.

However, I wanted more power, so I changed to a modern Ford internal regulator type alternator from a minivan. 95 amps and works great. It is a direct bolt in and only requires adding two wires to bypass the regulator.

Great info guys. Thanks.

I knew should have changed them as a set. *kicks self* I will change the regulator, check the wiring and have the new alternator checked.

Later, I will swap it for a internal regulator and fan version.

R.