[reno92]

If the alternator was working and the wiring is good, once the jeep is running the alternator should keep it running. You may have a bad alternator, or you may have bad wiring, either way your alternetor is not able to run the jeep and charge the battery.

 

[catcalls]

Does the alternator on a stock 92 4.0 go through the ecm before it charges the battery?

 

[catcalls]

Alternator tested good at Oreilly's. I think we have narrowed it down to a faulty voltage regulator. Since the computer has been bypassed, does the alternator feed power through the ecm before going back to charge the battery? If the voltage regulator was faulty could it have symptoms similar to this?

 

[Luckymac]

Boy oh Boy!! One thing after another.

It could be a faulty regulator, or it could be that since the computer is bypassed it no longer regulates power from the alternator to your battery. I am unsure just how your setup works.
Carburated stock YJs (like mine) have an integral regulator within the alternator. You may ned to find a regulator to work with your alternator, or find a early alternator. I am unsure what to recommend to you. Hopefully, other more knowledgable posters will chime in. Do you have a separate regulator?

An outside item to check is the wire that runs from your alternator to your battery (or power center). It could be corroded within the plastic insulation or the ends could be loose.

You can charge your battery overnight and run your Jeep for quite a long time as long (a couple hours) as you don't use your lights or radio.

Good Luck, L.M.

 

[216yj]

Try this it's free....

Get a piece of wood like a 2x4 as an extension and strike the alternator with a hammer a few times. If you're alternator starts working it's the brushes sticking.
If it works the alternator is in borrowed time unless you can rebuild it (I always just get a reman)
This just happened to me on the wife's van I pulled it and had it tested and all was good like you stated... Same scenario.

 

[roadyrob]

on a 92 the regulator is in the computer.

 

[jkp]

on a 92 the regulator is in the computer.

Yep.

 

[catcalls]

Will the alternator from an 87 bolt right on in place of my stock 5684 alternator from my 92?

 

[Nubby55]

No it will not. the older 4.2's use an alternator same as a GM, I think you is like a Nipideno < spelling is wrong, or Bosch.

 

[Luckymac]

Google "Quick Start Alternators" or "external voltage regulator conversion kit".
I am guessing the root of all your past problems might be your computer. You now have a HEI and a carb, so the next thing to buy is an external voltage regulator. I would expect that to cure your charging problems if your alternator is good like the parts counterman at O'Riellys said. Hopefully you will then have only the regular problemsthat we all get from time to time.

Good Luck, L.M.

 

[DREDnot]

Yeah, your 92 alternator is regulated by the computer. No an internally regulated alternator will not just plug and play. You will need to get an earlier 4.2L mount for the Delco-Remy style alternator and then wire it in to your system. Its not terribly hard. I did it on my externally regulated CJ 5.

You need to retrofit an 89-90 YJ system with the serpentine belt.