Bad alternator???

[Omahacj]

So first off I am a tech and have never had such a problem every before. Started with the jeep dying and wouldnt re-start. Has a brand new battery and had no output from the alternator so then I replaced it with a rebuilt 63amp and was fine till 4 hrs later and went to start it and nothing. tested for draw on the battery and was like .001ma nothing and shouldnt be since theres no computer and de-smogged. So I was scratching till some hair fell out the went to the alternator and tested under volts and has battery voltage to the output and when main pulled off drops to nothing. Gonna go exchange for warranty but curious if the diodes can bleed and if so how would one check that??

 

[BusaDave9]

Started with the jeep dying and wouldnt re-start.

Does it crank over? If so the starting system (Battery and starter) is okay.

If it cranks and won't start it sounds like the ignition system but it is also possible it could be fuel.
You could verify with a spark tester or pouring a LITTLE gas into the carb.

 

[Omahacj]

Thanks for the reply but the problem was the defective alternator diodes pulling amps from the battery with the key off. I do appreciate the reply though.

 

[73CJ]

Faulty diode shouldn't drain the battery.

What's the voltage running and not running?

14.3-15v running = charging. Less than that diodes or alt or regulator.

12.8 v or so for not running.

Now where is the .001 amp going?

 

[Omahacj]

Either diodes pulling amps due to being shorted or the regulator not shutting off not to sure. Swapped out now at 14.6 charging and 12.5 off. A bad diode will keep the charging circuit open with the key off.

 

[ftwflh]

Where is the "exciter wire " going too?

 

[73CJ]

Here's a diagram for 76http://www.jeep-cj.com/forums/f7/heater-fan-switch-3-position-toggle-8764/index2.html

 

[jasonmark1993]

Ha....dont see the alternator draining the batt situation much anymore.

Good job sticking to the basics.

 

[markc0000]

So first off I am a tech and have never had such a problem every before. Started with the jeep dying and wouldnt re-start. Has a brand new battery and had no output from the alternator so then I replaced it with a rebuilt 63amp and was fine till 4 hrs later and went to start it and nothing. tested for draw on the battery and was like .001ma nothing and shouldnt be since theres no computer and de-smogged. So I was scratching till some hair fell out the went to the alternator and tested under volts and has battery voltage to the output and when main pulled off drops to nothing. Gonna go exchange for warranty but curious if the diodes can bleed and if so how would one check that??

just had the same exact problem lol. took me a little over a week to figure out. it was bad wire for me. it was all green and nasty on the inside of the charging system wires. i got some good oxygen free wire new ends and dialectic for all the connections and it was good as new.