Junk yard alternator upgrade?

[DeadHammer]

So after driving my 98 4.0 TJ with the factory alternator for over 175,000 miles my accessories are starting to act a little funny. And my guage on the dash dips up and down with my engine rpm. I have heard that an alternator from a late model dodge truck or van puts out more amperage than the stock TJ unit and is a bolt in thing. So I'm looking for more information before I head out to the junk yard (part number, pulley swap, any necessary electrical modifications?). Has anybody done this before? I kinda want to swap the old factory unit out before it kills my battery and leaves me on the side of the road. I'm running a yellow top Optomia, will that make any difference in the alternator swap? I've looked into the after market alternators from Mean Green but don't have the cash for one of those.

 

[Rubicon Rich]

If your lights are flickering, I'd find out why. Is it the alternator or the wires? To see if the alternator is bad, put a volt meter on the output terminal of the alternator and check voltage. If it's off, it's the internal regulator. If there's no juice coming out, buy brushes and install them and polish the rotor with fine grit emery paper. It's a simple job.

 

[DeadHammer]

never mind :roll:

 

[wm69]

so what was the problem?

 

[Lucihale]

I'm curious too...

 

[DeadHammer]

Just got done changing the factory unit out with a higher amp one from a dodge truck, the old one was acting weak (lights and gauges dimming every now and then), I took it the old one to a shop by my house and they bench tested it on a good old sun-machine and found that the diodes were weak and under load it was only putting about 9.5-10 volts (hit or miss tested it 4 times). The alternator I got from the dodge truck was of higher amp but went right in and only cost 20 bucks off of craig's list (added new 4 gauge battery cables). I just wanted to know if anyone had ever done this parts inter-change before on a TJ.

 

[Lucihale]

Glad to hear it went well!

 

[Bounty__Hunter]

That's a good easy upgrade for any Jeep with the NipponDenso alternators.

 

[RockinCrawler]

I have been building dual alternator brackets

 

[DeadHammer]

RockinCrawler: have been building dual alternator brackets

I'd really like to see that, can you post some pics? I'm hope with this new alternator I can run a dual battery setup one battery for the stock electrical & the other to run my accessories (winch, fog light,CB etc...)anybody know how to wire that up?

 

[wm69]

Google Junk Yard Genius.

He's got some good diagrams on different ways of wiring up dual batt setups as well as alternator upgrade do's and don'ts.

 

[RockinCrawler]

Dual Alternator bracket

 

[RockinCrawler]

on this one I use a ambulance alternator 100 amp at idle and 160 amp max, along with the stock alternator

 

[hittin1]

I need to aquire 10 posts to send a private message to Rockincrawler. So I'll see if this gets too him. Please get in touch with me in reference to a possible Dual Alt bracket for my Jeep. I compete in car audio SPL competitions and would be interested in talkiung about you designing a bracket for my 1999 Jeep Grand Cherokee Laredo 4x4. Email - hittin1@hotmail.com phone- 337-438-2957 (cell) call me anytime day or night. Thanks, Mark