Battery light..?

So here is my problem.
In Dec. I had dead batt. problems so I had my alt. tested and it was bad.
Went through the "fun" of replacing it w/ a junkyard alt. and everything was fine for about 5 weeks.
Yesterday while leaving my neighborhood to go to work the batt light came on.
Today the car will not start. :help:
I know the battery is good b/c it isnt 6 months old, and it was tested at autozone not very long ago.

I didnt have time before work this morning to really look at it, but the connections looked ok at a glance.
Could my jy alt. be bad? :gun:
Or could it be something else?

Thanks for any ideas/assistance.

Sounds like it. Do you have a voltmeter? If you do start your car and measure the voltage at your battery terminals. It should be around 13.6 volts DC If it's around 12 volts or less and your car is running your alt is not working properly. If you don't have an voltmeter go to autozone and have them test it. Most likely your alt is bad. BTW you may have to charge your battery before you try this if you can't start the car. Sometimes people will suggest that you pull your battery cable off once the engine is running to determine if the alt is producing power. This works on older cars but can damapge the voltage reg in ours and newer cars. Doesn't always happen but it can. The voltage reg needs the battery present in order to properly regulate voltage out of the alt. You can get voltage spikes from the alt that can damage other systems as well especially in newer cars. Hope this helps
:cheers:

Make sure all the connections on the battery and alternator are good and tight. Also check the tension of the alternator belt, and the condition of the ground from the valve cover to frame.

Thanks for the replys.
It does sound like an alt problem at first but why would everything work fine w/ the new alt. for 5 weeks then just quit? Just its time?
I will be sure to check all my connections more thoroughly tomorrow.

Something as simple as the belt could be at fault too, eh?
I probably should have changed the belt when i did the alt, maybe that I will do that tom.
How tight should the alt belt be? I believe the manual said .02-.04 with 22 pounds of force on it, but thats kind of hard to determine.
When its cold I can push down on the middle of the belt and it will move a little but not very much.

*edit - I do not have a voltmeter but I guess I can take it up to autozone to find out.

Just make sure that the belt isn't real loose. Push on it in the middle and make sure it doesn't move down alot. Also try and look at the side that rides on the pulley. Look for cracks or if it is real shiny, change it. It could be slipping as the engine is running.

Well I did change the belt, tighten everything up and that did the trick.....for a week.

Yesterday on the way home from work the dreaded batt light came on when I started it up but mysteriously went off a mile or two from home.
I checked the belt tension and tried tightening up the nut on the tensioner and hoped it was ok.
Well this morning the batt light was back on, and of course the car is dead now as I sit at work. :help:
This is very frustrating. :gun: Why would the light come off and on.
I have now replaced the batt, belt, and the alt. The wiring "looks" ok.
I guess it is always a possibility that the j/y alt is bad but it seems like it has worked intermittantly.

i'm haveing the same problem, how was u able to get the alt out

Yep good posibility that the alternator from the junk yard is going bad.

Alright got a multimeter on it and running the car registered 14.2.

Does that mean that the alt is ok?

So what could the problem be then? bad wiring of some sort?
Any suggestions are appreciated.

and your batt. light still on??

Well I got a jump to get home and it wasnt on then. But I havent drove it or anything since. Just started it up a few mins ago to get the meter on it.

turn everything on then measure the volt's,
reply bac allright?

the carb guys may be able to confirm this, but,...doesn't the choke have some connection with the alt?........might be some intermittent fault there