Hi all, I have a 1998 Xj Limited with a newly remanned renix 4.0L. It was done by a custom engine building shop- great parts, great motor. When we replaced the motor, we also replaced just about every accessory as well( sat for a while, I had the parts.)

ne being the alternator- the bearing was squeeling intermittantly and would only charge at 12V's. So, I went to Autozone (in a pinch) and got another alternator; now that bearing is squeaking and hardly holding 13.5V's. the only extra accessory that is being ran is a 1000W amp for 2- 12" subs. This alone shouldn't cause a problem in lack of charging. The belt is new, and the tensioner is working correctly and is tightened down.

What is causing me to go through ALT's? I know they are poorly placed on these things- especially living in cold, wet Michigan.

 

Don't know about the first one, but I've had some big issues with AZ alternators being bad, right out of the box. Haven't put one on the Jeep, but on my son's pickup, we had to return the "new" one twice, and finally got a working one the third time. I hate that they are the only parts store close to me that is open somewhat late on a Sunday.

 

Powerful audio amplifiers will eat up cheap alternators. If you are driving 1000 watts RMS, you will want a 1+ farad cap and a higher output, better quality alternator.

 

Wow on the bad luck at AZ. I've been fortunate. Bought alternators there for my Jeep and chevy. I do have them test it before I leave the store. Biggest problem I've had with the charging has been the grounds. Since Jeep uses the ecm for voltage control, the grounds are serious concerns. Had a ecm commit suicide on itself trying to regulate the charging. Bad ground gave the ecm a good ground, bad ground charge/ no charge signal. ECM sent voltage and basically burned itself. Near fire. ECM spilled out white smoke, and shut down my Jeep. Best could figure was a bad ground.
Check grounds.

 

I've got a better CAP when I did a tuneup. I didn't think that 1000watt RMS would eat up a 90AMP alt that quickly...

It's like I blew the bearings on the alt's so far.

 

It shouldn't but parts store brand alternators have a pretty high failure rate to begin with and it could have been bad right out of the box.


Your best bet is a new (not remanufactured) Denso (OE manufacture) or Bosch, these cost a little more but are definitely worth it. If you don't mind grinding the bracket a little you can fit a 136A ZJ alternator as well.

 

Not a distributor cap. A capacitor to balance the current draw from the alternator. A 90a alternator is barely adequate for a stock XJ with no accessories.

A decent capacitor on your power source to your amplifier will improve its power output and performance plus keep voltage more even in the electrical system.

This kind of thing...

http://www.amazon.com/s?ie=UTF8&page...o%20capacitors

 

I bought one of http://www.ebay.com/itm/1996-Jeep-Cherokee-L4-2-5L-or-L6-4-0L-Engine-100AMP-Alternator-One-Year-Warranty-/150668892284?hash=item231490d87c&vxp=mtrabout nine months ago and haven't looked back. OK, I'm not running any big accessories but the price was right and the service excellent. Yes, it's a reman, but I can't fault it.

 

Ahh,, im not too familiar with a capacitor. But, I was thinking about buying one of RockAuto's 136AMP alts for 100$ or so. Then I should be able to add a winch and other accessories as well?

 

I put a 136a in mine. Pretty easy, just gotta grind a bit on the mount. I also upgraded to 4awg wires at the time.

If you're going through the trouble for that you could do a 160a alternator for about the same amount of work.

If you're interested in the upgraded wires check out kwip.com. John Kelley is the man when it comes to upgraded wires for these. He goes by the username "5-90" on several forums including here.

 

How far do you have to grind at the mount? I am a 23yr DIYer, pretty accomplished if I say so for my experience. Would this handled pretty easy with a steady hand and angle grinder?

 

It's worth noting it is only worth going to 160A if you plan on upgrading the wiring. The stock wiring and fuse are for 120A max so you won't be able to use 100% load on a 136A (but still 30A more than the stock alt) much less a 160A.

 

Thanks for the knowledge!

 

With remans it largely comes down to luck. Most remans these days just get new brushes and cleaned up (some remanufactures replace the bearings too, but many do not if they are still in spec), so if it was just worn brushes on the core you could get many years out of it with no problem, but if other components are worn (particularly if it is something not obvious such as insulation breaking down inside the rotor or stator windings) it could fail in a short period of time. Remans from Denso, Bosch, etc. tend to be good, but since they generally cost nearly as much as a new one (sometimes more than new until you get the core deposit back).

 

I just bought a good used 136 amp alt and took it to a local alt shop and had them rebuild and rewind to 160 amp cost $90 (I gave him 6 alt's also that I didn't need). Did Kelly's wiring upgrade plus second battery now good to go with my 9.5 winch and 2, 200 watt Amateur Radios plus all my lighting.


FYI to consider another path.