Alt. Light
Thread Starter
Instructor
Joined: Jun 2001
Posts: 220
Likes: 0
From: New Jersey
Alt. Light
On my 76 Euro 911 sometimes the alt light stays on a few minutes after I start the car with the car idling 900 or above.After a few minutes of driving it goes out.It will also go on and off again while I'm driving.The car always started fine,but last weekend when I went to start it and the battery was dead.Before I check the alt/regulator has this happened to anyone else and what was the solution.
Maybe a bad ground.I charged the battery outside the car and going to see if it holds a charge without being hooked up to the car.
Thanks,
Steve
Maybe a bad ground.I charged the battery outside the car and going to see if it holds a charge without being hooked up to the car.
Thanks,
Steve
Drifting
Joined: May 2001
Posts: 3,291
Likes: 6
From: WI, US
Steve:
I had similar simptoms on my '86 when I owned it. Alt light would go on right after starting and go away after a minute or so of driving and then flash every once in awhile while driving. Dash lights seemed dim too.
I had my alternator rebuilt and the problem went away. Some of the brushes on the armature of the alternator were worn enough that they were not making good contact anymore. The output of the alternator was no longer keeping the battery fully charged or providing enough current to run the electrical needs of the car.
You can do a simple check of the output of the alternator. Put a multi-meter on the battery when the car is not running. It should read slightly above 12 volts. Then start the car and see if you can have someone hold the throttle so the car is running at a fast idle. The volt meter on the battery should ready about 14 volts. If not, you have a charging problem.
Good luck,
Jay
<a href="http://www.jays911.com" target="_blank">90 964</a>
I had similar simptoms on my '86 when I owned it. Alt light would go on right after starting and go away after a minute or so of driving and then flash every once in awhile while driving. Dash lights seemed dim too.
I had my alternator rebuilt and the problem went away. Some of the brushes on the armature of the alternator were worn enough that they were not making good contact anymore. The output of the alternator was no longer keeping the battery fully charged or providing enough current to run the electrical needs of the car.
You can do a simple check of the output of the alternator. Put a multi-meter on the battery when the car is not running. It should read slightly above 12 volts. Then start the car and see if you can have someone hold the throttle so the car is running at a fast idle. The volt meter on the battery should ready about 14 volts. If not, you have a charging problem.
Good luck,
Jay
<a href="http://www.jays911.com" target="_blank">90 964</a>
Intermediate
Joined: Jul 2001
Posts: 39
Likes: 0
From: Australia
Hi, I have seen that before. Sometimes when the car has an old external regulator, the points in it can be a little worn and sticky after a few years. Check it, if not the problem, it could be the belt is a little loose or the alternator may be no good.
I got a new unit from <a href="http://www.aasesales.com" target="_blank">www.aasesales.com</a>
Just keep an eye on it with a voltmeter.
Saint
I got a new unit from <a href="http://www.aasesales.com" target="_blank">www.aasesales.com</a>
Just keep an eye on it with a voltmeter.
Saint
Advanced
Joined: Mar 2002
Posts: 89
Likes: 0
From: Madrid, Spain
I had to replace my Alt last x-mas, as it would do something similar, except that the alt light would not come on at all...
It seems these babies give up at a certain mileage, although you should check if you can rebuild it (they are expensive)
I am planning to keep my car over the long term, so a new alt & regulator was the way to go...
It seems these babies give up at a certain mileage, although you should check if you can rebuild it (they are expensive)
I am planning to keep my car over the long term, so a new alt & regulator was the way to go...
Instructor
Joined: Apr 2002
Posts: 115
Likes: 0
From: Albuquerque
My light comes on after I start the car and it's at low RPM...once I rev it up over 1000 the light goes out and stays out...so I don't know if mine is normal or in the beginning stages of going bad.
Drifting
Joined: May 2001
Posts: 3,291
Likes: 6
From: WI, US
H.D.
The first symtoms of my alternator failing where exactly as you describe above. The Alt light would come on at start and once the motor was rev'd, it would go out. Then it progressed to what I posted in my first post above.
I was able to get my alternator rebuilt at that time (1999) for $122 at a local starter/alternator rebuild shop vs. paying $250-$600 for one from the dealer or mail order.
Jay
90 964
The first symtoms of my alternator failing where exactly as you describe above. The Alt light would come on at start and once the motor was rev'd, it would go out. Then it progressed to what I posted in my first post above.
I was able to get my alternator rebuilt at that time (1999) for $122 at a local starter/alternator rebuild shop vs. paying $250-$600 for one from the dealer or mail order.
Jay
90 964