eating alternators

[datrod]

O.K. my alt went out last weekend so I take the battery and alt down to the parts house. Batt is O.K. but the bearing in the alt was bad. So they sold me a new alt. Now I just drove the car for a few miles. And today car won't start.

WTF!!!!!

[ggzilla]

Bad bearing won't cause charging problem. It just be noisy.

 

Perhaps you left the lights or radio on?

[datrod]

No I didn't leave the lights on. Hell I never drive it at night.:lol:

And the radio turns off with the key.

[datzenmike]

Turn everything off and connect a test light between either battery cable and the battery post.... if it lights up something is drawing power.

 

Unplug the alt and see if it stops.... then pull each fuse till it goes out and this is the circuit with the draw.

 

Could be the external regulator if equipped.

[datrod]

Turn everything off and connect a test light between either battery cable and the battery post.... if it lights up something is drawing power.

 

Unplug the alt and see if it stops.... then pull each fuse till it goes out and this is the circuit with the draw.

 

Could be the external regulator if equipped.

 

There is a large ground wire comming out of the same loom that hooks up to the alt. It was not even touching any metal. So I'm guessing that my alt was not grounded Correct? I took the alt to the auto parts store and it checks out fine. So charge the batt and tighten the ground and I should be on my way.

[ggzilla]

Maybe. The alternator also grounds through the bracket. The ground wire is just in case.

 

Charge the battery, then start the engine and test the Voltage at battery when running at 1200 RPM. If it is 13.5-15.0 volts all is well.

[datrod]

Thanks guy's. I'm having the parts store charge the batt and I'll go pick it up in a few minutes and see what happens. I think I might buy one of them little gages. So I know how many amps I'm pulling with the stereo and all running.

 

The first thing the kid at the parts store asked me was do you have a system.

I'm like NO but I have a stereo in there. :lol:

[ggzilla]

Forget the ammeter. Get a voltmeter, it's far more useful.

[datrod]

Thanks gzilla.

O.K. so i put everything back on the car. It starts but when I disconnect the positive cable it dies. Would that be the regulator that's not letting the alt work. I'm a complete dumb ass when it comes to anything with wires. :(

[ggzilla]

You cannot tell what the exact problem is by pulling the cable. That only tells you that something is wrong.

 

You need a voltmeter, ask a friend with one to stop by.

 

* If the voltage is higher than 15.0 volts, the regulator is bad and it's good bet that is has damaged the battery.

* If the voltage output is low, hot-wire the alternator and check the voltage again. Directions are here: Datsun Alternator testing

 

Regulator bypass testing

Edited August 2, 2009 by ggzilla

[datrod]

Cool thanks. I'll check it in the A.M.

[Duke]

I'm a complete dumb ass when it comes to anything with wires. :(

 

 

All I know 'bout them wires is they run on smoke. If you let the smoke out, it don't work no more.

[datrod]

All I know 'bout them wires is they run on smoke. If you let the smoke out, it don't work no more.

 

:lol:

[datrod]

Got it. The regulator was bad. And I also had some bad wires down there so I kinda fixed thm. I need to go back and fix them all soon.

Thanks for the help ggzilla & dmike :D

[ggzilla]

Glad to hear. Another Datsun back on the road!