car runs on only the battery

[cluna]

So its a 76 and the battery is new same with the alternator and volatge regulator but still no luck if I run it with the lights after a little while it will die. I'm not sure what to try next

[Guest Anonymous]

...Sounds like the car still isn't charging. Is the charging light on?

[Patman]

I am not an expert by any means but I know that an alternator needs power to create the field to charge the battery. You might want to check that you have all the wires connected.

Good luck!

Patman

[Patman]

Here is the wiring diagram for the charging system. Check the lead from the key thru the regulator to the alternator.... I would guess your issue is there:

http://www.bmw2002faq.com/content/view/36/32/

Patman

[jmp88]

I know that an alternator needs power to create the field to charge the battery.

Yes, the battery-charging field... You should also check your flux-capacitor while you're busy with that field.

Patman has a good point though that if your whole charging system really is new you should go through and double check all of your connections. Is it the stock alternator or is it an upgraded 65 or 80 amp one? If it's the stock one it'd be hard to mix up the wires since they're all on that one big plug.

How new is the alternator? Is it really new or is it rebuilt?

[cluna]

We have checked the wiring. Its good its. A rebuilt. Alternator

[jmp88]

I would guess the alternator is bad. As far as I know the voltage regulator is fairly durable and there's really nothing more to the charging system than those two parts. I don't know how to check an alternator but you could always take it in to an alternator shop I suppose. They probably wouldn't charge you much if at all just to test it out.

[mossyboy6]

go to harbor freight and get a $3 multimeter

FIND your problem

Replace when necessary

[hnichols]

I'm not sure if this is helpful, but I always thought a quick way of checking an alternator is by seeing if a screwdriver sticks tightly to it when it's running.

Someone who knows something can of course correct me.

Good luck!

Hugh

[jmr_1602]

+1 on getting a mulitmeter.

Have you made sure your alt. belt is tight enough?

[cluna]

I have multimeter and checked it and its good but still hving the problem