XJ Eating Batteries?

DISCLAIMER: I am NOT good with vehicle electrical systems... Never have been. I think there is magic in them there wires :laugh3:

About a week ago the XJ slid sideways out of a rut and landed us in some fairly deep water... The front drivers wheel was nearly underwater... It took about 15-20 minutes to get it out. By the time we were done, I had about 3 inches of water in the drivers footwell. Everything seemed fine for a couple days until the "Check Gauges" light came on and the battery was pegged at 9 volts...

Took it home and charged the battery. Next day, battery 100%, made it less than 1 mile from the house and same issue. Battery reading 9 amps.

Thought I fried the alternator (original 170K miles). No big deal... Thought i would "treat" the Jeep by buying a NEW one!

New alternator in, no issues for two days... Then the same thing happened.

Swapped a different battery (same type) into the Jeep, same issue...

At this point I have a new alternator, and good battery. SO... now that I have read all threads about the things that can possibly be wrong, I have come out more confused than before :helpme:

Please do not be too hard on me...

1998 XJ 4.0L
HTT

Have you had the other battery checked to make sure it is really "good"?

Yes, I have taken both batteries and had them tested. Both have been put into te Jeep 100% full.

HTT

At least on my '95, Fuse 1 and Fuse 9 are for the alternator. Perhaps when things were wet, those fuses blew. They are 60 amp fuses.

David Bricker / SYR

Also, can you measure the voltage at your battery? If the alternator is charging, you should run about 13.2 Volts, or a bit higher is the battery is down. If the alternator isn't charging, and the battery if full, it will be about 12.7 Volts.

David Bricker / SYR

After topping the battery off again over night, it read 12.6v across the battery before i put it in the Jeep. After i put it in the Jeep and started it, it read 14.1 across the battery. I turned on everything i could (headlights, fan on high, radio, flashers, and all interior lights) and it read 12.5 across the battery at idle. At higher RPMs it went up to about 13.6.

I turned everything off again and it returned back to 14.1.

Okay, i cranked all the accessories i could and let it sit at idle. The voltage across the battery slowly dropped until it plateaued at 12.1v - 12.2v. If i increased the RPMs the voltage across the alternator would increase.

I hope this information means something to someone...

HTT

In the time it took me to post that last message, i went back outside and the voltage across the battery is back up to 13.9-14.0 and had been idling for about 10 minutes...

HTT

Ok just as a sanity check, i took it for a drive and before i got a mile away 9v and "Check Gauges" light on again. At least it is consistant...

And thoughts or direction to point me in?

HTT

Check your 60 amp alternator fuses under the hood.

All fuses under hood are good.

Sounds similar to the problem I had with the aftermarket alternator. At low RPMs, it wouldn't charge. It would only charge decently above 2500 RPM. Problem is most of my driving is under 2500 RPM.

A fully charged battery at rest should read about 12.6-12.8 Volts. A properly operating charging circuit should run about 13.2-13.8 Volts, depending on the charge state of the battery.

Sounds like you have an alternator that isn't charging well at low RPM. Yes, I know you just replaced it, but, the alternator seems suspect.

Also, check connections for looseness, corrosion. Be sure the battery posts are scraped/brushed clean, not just look it. They should be shiny, not dull. Make sure the connection to the alternator doesn't have a bunch of wires broken at the terminal end. Finally, verify your engine to battery to chassis ground are solid.

David Bricker /SYR

Rereading your last couple of posts, I would suspect grounds or poor connections someplace. The fact that you took it for a drive (moved the connections a bit) leads me to this thought. If this started after having been submerged, you may have gotten some corrosion into the ground connections.

David Bricker / SYR

Yes, it starts and runs great. Positive and Negative terminals have been cleaned. I drove it to work and back (40+ miles) the first day it happened and the only thing i noticed when i was almost home was my wipers moving slow...

I am going to charge up both batteries I have and take the Jeep to AutoZone or Advance and have them test the alternator...

HTT

Alternator check out as good... any other thoughts?

Just because you cleaned the terminals doesnt mean the cables are good.

^ this
i would physically unhook the cables on the alternator and the power block and clean the SNOT out of all of them..
then double check all of the grounding straps and clean them too

I had this issue for one day and it was the wire on the side of the alternator

ALSO!!! on a side note
autozone and advance suck at checking alternators and starters
i have all of mine recoiled at a local electrical shop when they go bad.
i refuse to buy aftermarket ones after i had two in a row be faulty but check out as "good"

Don't overlook ground connections. Ground wire from battery to engine, from engine to body, from engine to alternator, if there is a separate wire.

If necessary, as a temporary measure, connect a separate ground wire from the alternator case to the battery ground terminal. Just be sure it is of decent size (12 gauge), not some sleazy piece of left over speaker wire.

David Bricker / SYR

Tacedaddy said:

^ this
i would physically unhook the cables on the alternator and the power block and clean the SNOT out of all of them..
then double check all of the grounding straps and clean them too

I had this issue for one day and it was the wire on the side of the alternator

ALSO!!! on a side note
autozone and advance suck at checking alternators and starters
i have all of mine recoiled at a local electrical shop when they go bad.
i refuse to buy aftermarket ones after i had two in a row be faulty but check out as "good"

Click to expand...

I will give this a shot this evening. Thanks for all the help. I will update as soon as i have one...