Altenator Light Issues

[doclees]

This is an ongoing saga folks. Here is the background. 93 atx. Over the past 3 years has had intermittent no start issues. This means turn the key and nothing. I am on the 3rd LLT starter in 3 years. Battery is good. 12v engine off. I had issues with the ignition switch that may or may not have had input to this problem. I just replaced that switch with no change in the problem. Up until today I have not had the Alt light come on. The car would start. Drive a little and maybe no start. Let sit for 1-4 hours and it starts again. This morning I cleaned the neg battery post and clamp type cable head. Seemed to give me a stronger alarm beep. I drive to work and the Alt light comes on only over 1500 rpms. Lunch I try it again and no start and week alarm/lock action. I clean the neg battery cable again with it sometimes setting off alarm when connected and sometimes not. I clean the pos cable clamp and post. Strong alarm and lock action. Start up. Alt light still only over 1500 rpm. Starts up a couple hours later. I go home about 25 miles away. Alt light sometimes doesn't come on until 2k rpm. At home I park it and restart it. No problem. Now alt light constant but flickers sometimes. tonight I check a prong connector on alt. No change. Car starts no problem. Volt meter give me 12.05 engine off. 11.50 engine on. Is there a positive test for alt function I can do at home with my voltmeter? Why reliable starting now but alt light? Could I have stressed something to **** the Alt?

Had to drive car today about 5 miles. Started fine. Was at location about 20 min. No start. Lots of relay clicking. reseated bat cables. No change. Lights strong. Alarm strong. Windows weak. Had someone try to jump it. No change. Got a ride home. Help! I'll go tonight and it will start.

 

[Rob94]

With the engine running, you should be getting over 12 volts across the battery terminals. If, with the engine running, you are only getting 11.05, the alternator is junk.

 

[doclees]

Thanks Rob94
Here is the update: Pulled battery from 89 SHO. Charged overnight on bench charger. Started great. No alt light. Got it home. Voltmeter reading 12.5x. Took it to Advance auto and had system checked. Battery was a little low but good and taking charge. It had sat for 4 months. Alt only putting out 12.5 volts so that is low and amps were 165. But then he said his equipment said no output. So maybe it is on the way out but not dead. Just enough charge to keep the battery alive most of the time?
In the olden days we had separate regulators. This is what they did when they went bad. You could jump the contacts with a no start like this. Never had an alt die a slow death.
I guess if I pull it and have it bench tested it will rule out a connection or drain issue.

 

[TankII]

Similar problem just happened on my '91.
Turned out it was the rectifier assembly. My rebuilder found it during testing.

BTW, when he got done with the unit, it was putting out over 100 Amps.

International Auto, 16 Spring Street West Hartford, CT 06110
(860) 953-6999
Ask for Peter (the owner)

Granted, I dropped it off, but the turnaround was three days. He always uses new parts, so the bearings, brushes, regulator, and rectifier were replaced. Most rebuilders just do the bearings, regulator and brushes, hence their minimal pricing.


TankII

 

[doclees]

Just to end this thread it was the alternator. Well at least it has started the last 14 times and no alt light. See my other thread to see the history.