engine starts.......then dies

[ShafferNY]

From my understanding, the KJ doesn't have a traditional charging system made up of separate componets like vehicles past. The voltage regulator and rectifier is built into the PCM.

Perhaps this accounts for everyone's experiences with weird things happening when the KJ has a battery that is weak. Not enough juice to power the PCM correctly results in poor operation.

If it were a traditional setup with separate componets, then I totally agree with Powerslave. In fact, it SHOULD be designed to operate as such. I'm just not sure it is.

 

[kb0nly]

Yep, the regulator is NOT part of the alternator on them, the PCM does all the work.

That gel cell worked like you said because it was evidently a good battery and taking a charge from the alternator after the engine was jump started, if the battery was bad, or no battery at all, then it won't run with the charging system they have, that's all there is to it.

Back in the old days if a vehicle had a bad battery, dead cell or such, you could literally disconnect the battery and tape off the positive cable and jump start the vehicle and it would run off the alternator as long as you didn't turn on anything else and put a strain on it, used to do that with the tractors on the farm all the time when a battery went bad and we didn't have time to go get a new one. You couldn't do that with the KJ as the PCM would sense there is a problem with the battery because there is no feedback from the regulator circuit and would then shut down the field in the alternator and no charge. Same thing if the battery was bad or presenting a partial short because of a dead cell.

I could go into more technical detail on the charging system in the KJ by quoting the service manual and explaining the electrical theory behind it, but lets just say this, no good battery no worky....

All i know is with all the reports on here and other Jeep forums of runability problems that were solved with a new battery i believe it!

 

[ry1820]

i went to start my car this morning and it cranked fine and started, but then it just quit. i tried it four or five times and it just quit. finally i just gave it gas while starting it andd it stayed running but it ran like absolute crap! then i put it in drive and drove around the block and the problem went away...for now. then, after work tonight it started fine but my AVG MPG and timer on my EVIC were showing zero. my dad thinks that it is the battery which i think so also but i dont know much about electrical. a few weeks ago i went to autozone and they hooked up the computer thing to my battery and alternator and they said that everything was fine i know that autozone isnt the smartest but are they right? or is it my battery that is causing all this to happen?

Im new to this forum...actually I have an o4 WJ - so I shouldnt even be here. BUT I am having the SAME EXACT problem with mine. No one seems to know what it is.... even the folks over at jeepforum who have usually been so helpful over the years.

Has this been resolved (hopefully it has over the past year!)
I sent kbooneKJ a PM as well.

Thanks in advance for any help!

 

[ThunderbirdJunkie]

The only people that have issues out of their Jeeps are the ones that call them cars.

Just sayin'

 

[mag03kj]

(lol)

 

[ry1820]

The only people that have issues out of their Jeeps are the ones that call them cars.

Just sayin'

haha...didnt catch that... (rotflmao)

 

[Nooby]

when my battery died the first time,
it wouldn't start, but when I gave it gas(floored it), it would almost start, or at least try to turn over, my Jeep made alot of clicking from the rear door latch next to the spare tire when the battery was dead too, even when you didn't hit any unlock or lock buttons

 

[ry1820]

I suppose I will replace the battery. I hate to do so just to try something, but it is the original battery and I guess it can't hurt to replace it.

If anyone else has had a similar problem, please let me know what you did!

 

[Nooby]

also, on another car, the battery left me sitting 2x and occasionally at a light would feel like it was going to stall, each time it let me sit, I got a jump when to advance auto and they checked out the charging system and said it was fine and that the battery was good

needless to say after the second time i replaced the battery, didn't have any other problems with the car(yes car, not my jeep)

 

[mag03kj]

I cant get mine to do anything when i try to check codes!

 

[ThunderbirdJunkie]

False.
Mine has never said done when I've checked for codes.

ThunderbirdJunkie's KJ doesn't do it unless there are stored codes.

 

[kbooneKJ]

I forgot starting this thread last year until it got resurrected. The battery in my new kj is stock, no problems YET but im sure this summer will be hell if I dont get a new one. It kind of makes me wonder how many jeep-clueless owners have had to spend a ton of money replacing parts when all it was was the battery.

 

[Tamarindo[ITA]]

The only people that have issues out of their Jeeps are the ones that call them cars.

Just sayin'

...quote of the year...

 

[kjweston]

Mine had the same problem. wouldnt idle and stay on. turned out to be a bad cell in my batery.. bought a new red top and have been going strong since.. and my dash displays 'done' when there arent any codes..

 

[New Liberty]

Mine shows codes when they are there, but it has never said 'done' if there were no codes.

Weird. In my search for my KJ, I've been in 5-6 '04 KJ's over the past couple of months. With the exception of 1 that actually had a code to present, they all displayed "done" after performing the sequence.