Another Alternator Thread...

Hey all,

I have a chronic battery issue in that the jeep goes through them too quickly. I get about 2 years out of them. I've changed the alternator, have performed a bunch of testing, have figured out that I need to install new cabling that I'll be contacting 5-90 for, and I may have a charging issue related to the ECM.

I found this website: https://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html that permits the voltage to be regulated without the ECM.

So then I got to thinking, can I install a late 80's XJ alternator on my 1996 XJ that is internally regulated? Will it physically fit? Anyone know?

Thanks,

Wes

What makes you think the ECM is not regulating the voltage correctly?

What did you replace the original alternator with? I can tell you that I replaced my original one with a Duralast from Autozone and it performed worse than the original did, especially at idle. What kind of accessory load do you run? I have some high wattage KCs tied in with my high beams. When I have all my lights on, my heated seats on, and the e-fan clicks on I can watch my voltage gauge drop at idle. I have a Powermaster 160 amp alt waiting to go in along with some beefier cables. I just haven't had time to install them yet.

My guess is you need some heavier duty cables and a higher amp alternator if you run a lot of accessories. A stock replacement alternator won't help the situation, and one from a 1980s XJ which produced even lower amperage (usually around 90 amps) will probably make the problem even worse.

A V8 ZJ alternator is a good place to start, they put out more amps and can bolt right in with a little grinding on the bracket.

The voltage output measured with the voltage gauge and with a volt meter never exceeds 13.2V or so. Charging voltage should be higher with a low battery. With this condition, it would make sense, to me, that premature battery failure would occur, which is another symptom.

This jeep is pretty stock. It is a country model with no additional accessories or big stereo.

My quandary is - I don't want to get new cabling and end up needing to change it due to doing an alternator mod. When I replaced the alternator, I just went to the local Autoparts (Carquest) and bought what they had. Couldn't tell you what the rated output is...

The last time I bought a parts house alternator, I had to exchange it 4 or 5 times to get one that worked right.

I would suspect you replaced bad parts with bad parts.