'82 Alternator Charging

So I suspect I have a failing alternator, but I've never had an alternator in the back of the car before on a Ferrari so I wanted to check.

I'm getting no charge at idle, but at about 2500 or so RPM it charges up to 14.

Normal, or failing alternator?

Thanks guys!

 

As for 328 it is normal that when starting the charge light keep on until you rev more then 2.000 RPM. For a 308 others should shim in.

 

Yes I know that is normal. The exciter needs to be activated for the thing to start charging. This is after the light goes out.

 

On my 79, my alternator light is never on at idle (1000 RPM). If yours is on at idle, then you probably need to overhaul your alternator. It can only be brushes or the regulator, if it's charging at higher revs. At least on the 79, the regulator and brushes are one easily replaceable module.
The only problem is getting the alternator out of the car
I just rebuilt my alternator ("while I'm in there")... two bearings, good cleaning, regulator/brushes module. Was simple using this video...

 

My light is NOT on at idle.

The light goes off as soon as I rev it which is completely normal. It doesn't come back on or anything.

What I'm asking is-- is it normal for the alternator to not put out 14v at idle?

I don't think it is but I'm just trying to confirm.

 

The ignition warning light does not really confirm alternator health-it is the balance between battery discharge and alternator charge. But once started it should go off and subsequently show 14.4v ish at any rpm.

 

Definitely not normal. You should be getting around 14 V at idle sounds like you might have bad diode inside

 

Thank you sir!

 

Alternators that put out 14V (or more) are more of a recent thing. Something like ~13.5V (even at higher RPM) would be more normalish for your vintage of car. What voltages are you getting at the battery at 1000 RPM warm idle with:

1. Headlights "off" and AC blower "off"?
2. Headlights "on" and AC blower "off"?
3. Headlights "on" and AC blower "on"?

 

My observation is it's normal. I have seen it on many 308's. My ECU data recorder usually records around 13.2-13.3 at idle with a fully charged battery. You will see higher voltages when the battery is in a discharged condition while it is recharging heavily.

 

It isn't charging at all at idle. Once I give it a little gas it goes up the more gas I give it. So it reaches about 14v but only at around 2500 or so RPM.

I have a new one on the way so I'll post my findings.

 

when i started my car the alt light would stay on till i rev it up but i just replaced the timing belts and alt and a/c belt i used the (gates) app that helps you if the belt tension is good now no light at all and charging 14volts at idle