Need help with a battery issue in my 04 LJ.

[TFRI]

I started having issues a few weeks ago with my jeep starting in the morning. all of the gauges come up. the clock and trip odo reset. with a few pushes on the gas I can normally get it to start. I have been using my Battery Tender JR over night and it will run great that day. the next morning same problem as before. I'm not sure if it is the battery, the alternator or the PCM. I'm running Optima Yellow Top (It was in the Jeep when I bought it, so I don't know how old) and stock alternator.

I have read a few articles about the stock alternator not having optimal output to keep a deep cycle battery in the best condition. I also read that the PCM for this year (it has a power regulator for charging the battery on the board) can malfunction and cause charging issues.

I am not sure where to start troubleshooting and all replacements are a little spendy... Any help would be great!

Thanks! -T

 

[jeep-N-montero]

I have the yellow top in both of my Jeeps with higher output alternators and couldn't be happier, so you could indeed be having issues with the battery not fully charging. This is why so many people think their Optima is dead prematurely when in fact they are simply under charging them. And that battery tender may actually be doing more harm than good.

 

[TFRI]

Is there a recommended amp output for the alternator? What kind of charger should I be using to get this thing back into shape?

 

[irish1371]

i would check/flex all your grounds and battery cables for corrosion hidden under the plastic. Also check your wiring to the alternator

You can go to any auto zone and get your alt and battery checked for free to see if they are the issue also

 

[bob91yj]

I've never had an issue with the alternator on my LJ keeping an Optima yellow top charged, factory alternator is approx 115amps if memory serves. I'd suspect a faulty battery. Most Auto Zones will do an electrical test at no charge.

 

[1stDeuce]

Do you have a volt meter? If not, get one! You need to check voltage at the battery with the engine running, and after at least a 5 minute drive. You should see about 13.8 volts with most everything electrical turned off. Then turn on the headlights, turn the heater to high, and if you have it, turn on the rear defroster. go check voltage again. It should still be above 13 volts and preferably nearer 13.8 still. If you've got less than 13 volts with the engine running and the car's accessories on, I would suspect either the alternator is getting weak, or the PCM is charging to a low voltage, which will kill the battery. If voltage looks good for both of those tests, then suspect that the battery is on it's last legs. This would be somewhat supported by the fact that it's starting better when you charge it overnight... It would have a higher surface charge, which would start the engine faster. If that is the case, it should also start good right after you shut it off after some driving. Have the battery tested at the auto parts store, don't replace it with another optima, or use a red top if you do. (I have better luck with the red tops, but the best batteries I've had said Everstart on them.)

Gel cell batteries (Like optimas) do have different charging requirements than flooded lead-acid batteries, but normally, you're not discharging them much, so they are reasonably happy in most auto applications. Jeep actually charges at a slightly lower voltage than many auto makers, so they're one of the better platforms to put gel batteries into IMO.
Good luck.
C

 

[TFRI]

i would check/flex all your grounds and battery cables for corrosion hidden under the plastic. Also check your wiring to the alternator

You can go to any auto zone and get your alt and battery checked for free to see if they are the issue also

I have checked for corrosion. I will look at the wiring to the alternator and go have it tested when I get home. Thx! T

 

[TFRI]

Do you have a volt meter? If not, get one! You need to check voltage at the battery with the engine running, and after at least a 5 minute drive. You should see about 13.8 volts with most everything electrical turned off. Then turn on the headlights, turn the heater to high, and if you have it, turn on the rear defroster. go check voltage again. It should still be above 13 volts and preferably nearer 13.8 still. If you've got less than 13 volts with the engine running and the car's accessories on, I would suspect either the alternator is getting weak, or the PCM is charging to a low voltage, which will kill the battery. If voltage looks good for both of those tests, then suspect that the battery is on it's last legs. This would be somewhat supported by the fact that it's starting better when you charge it overnight... It would have a higher surface charge, which would start the engine faster. If that is the case, it should also start good right after you shut it off after some driving. Have the battery tested at the auto parts store, don't replace it with another optima, or use a red top if you do. (I have better luck with the red tops, but the best batteries I've had said Everstart on them.)

Gel cell batteries (Like optimas) do have different charging requirements than flooded lead-acid batteries, but normally, you're not discharging them much, so they are reasonably happy in most auto applications. Jeep actually charges at a slightly lower voltage than many auto makers, so they're one of the better platforms to put gel batteries into IMO.
Good luck.
C

I do have a volt meter. I will try this out before heading to Autozone to get things tested.

I'll report back later...

Thanks you everyone! This community rocks!

 

[TFRI]

So it looks like the alternator is good. it's running at 13.6 to 13.8 volts after starting. after a 5+ min drive it was running at 13.8 volts. A quick drive over to AutoZone and they are telling me it's at 86% and won't take a charge. so now ordering a new battery.

T

 

[bob91yj]

Lesson learned, start with the simple stuff! There is a catchier phrase that applies in my case, K.I.S.S. (keep it simple, stupid).

I had a driveline vibration in my YJ years ago...let's see if I can remember...

Decided it was the tcase, pulled it, overhauled it (chain was slightly stretched), put it back together, not fixed.

Decided it was in the transmission, pulled the tcase/trans, swapped in a spare transmission I had that had the external slave cylinder, put it back together, not fixed.

Decided it must be my driveline angles, installed a Daystar 1" body lift, and 1" engine mounts, STILL not fixed.

Finally decided to put it on jackstands and run it, removed the rear driveshaft for the THIRD time so I could run just the front end, noticed the CV joint was floppy/loose, took it to my driveline guy, he rebuilt the CV, put it back together...FIXED!

On the plus side, I got a lot of stuff done my Jeep that had been on the back burner for a while!

 

[jeep-N-montero]

So it looks like the alternator is good. it's running at 13.6 to 13.8 volts after starting. after a 5+ min drive it was running at 13.8 volts. A quick drive over to AutoZone and they are telling me it's at 86% and won't take a charge. so now ordering a new battery.

T

I am almost willing to bet money that the monkeys at Autozone did not properly test the battery, this is how I ended up with 3 yellow tops that tested "bad" at auto stores but were properly tested and resold by my local Interstate distributor.

 

[TFRI]

I think i'm going to go with the Sears Diehard Platinum as a replacement. It has more cranking amps, larger reserve, and 2 year longer warranty.

Specifications
Dimensions:
Group Size: 34
Height (In.): 7.8
Item Weight (lbs.): 53.0
Length (in.): 10.9
Width (in.): 6.8
Power Ratings:
Amp Hours at 20 Hour Rate: 68
Cold Cranking Amps (CCA at 0 deg.F): 880
Reserve Capacity (RC): 135
Design & Construction:
Battery Design: Absorbed Glass Mat
Battery Grade: Die Hard Platinum
Container Material: Polycarbonate/polyester
Maintenance: Maintenance Free
Overall Type: Deep-cycle
Temperate Zone: North or South
Terminal Post Location: Top
Warranties & Coverage:
Free Replacement Warranty Term: 48 Months
Months in Use Pro Rated Replacement: 100

 

[TFRI]

I picked up my platinum last night and will be installing it today. I also picked up a new charger/jumpstart unit that should take care of any battery I will own for a while... I am going to try to recondition the yellow top to use it in a dual battery setup.

 

[DarinM]

I had similar problems with my 04 TJ Rubicon this summer. It was slower and slower on startup, alternator was showing a good output. I'd pull the battery and charge it overnight, the Jeep would start and be fine for a couple days, but it eventually got to where the output on the battery would drop to about 8 volts from unhooking it from the charger, carrying out to the jeep and testing it. Thankfully I got a free replacement because it was still under warranty (by about 2 months on a 3 yr battery!). I also learned that it's not much fun to put a battery in a backpack and carry it via motorcycle.
Next projects - front outer axle seals, rear pinion seal, and who knows what else. Since I just moved to Wichita, I'm gonna be driving the Jeep more again. There were very few days last year in Austin when I couldn't ride my motorcycle to work - don't think that's going to be the case here.

 

[Hill Bill E.]

I started having issues a few weeks ago with my jeep starting in the morning. ............with a few pushes on the gas I can normally get it to start. .............

Thanks! -T

That right there tells me that your battery either isn't above 11-12V, or it dropped below 11-12V during the night.

The ECU needs a certain amount of voltage in order to start the engine normally (I think it's 10.8 or above, not positive)

When the battery drops below that voltage, you need to apply the throttle in order for it to start/run/idle.

Once started, the alt takes over, and the ECU is reading enough volts to keep the engine running.

You shouldn't have to touch the throttle at all when starting newer, EFI engines.


On my XJ, the PO relocated the 'vacuum ball' when he installed an aftermarket bumper.

Turns out, where it was relocated at, it pushed on the main wiring harness. In turn, the harness rubbed on the injector rail, and grounded out the wire that the ECU uses to tell the ALT to charge.

I had either a 'no charge' or an 'overcharge' situation when running. Took a while to find that gremlin!

I think a new battery will solve your issues.