Alternator problem?

[lbeothuckl]

So I started the Jeep up and I thought there was a whining sound coming from the engine area. I popped the hood and couldn't locate the sound. So I gave it a rev and the headlights blinked and it seemed like it was going to shut down. I took it for a ride to see and she seemed to behave normally. I would say half the time if in park or neutral when I rev it uo to about 2000 rpm as the rpm's come down they seem to go down to far, when they reach their lowest point the headlights blink the rpm's always come back up.

I checked the battery and it has a good charge but the alternator % meter that is on my charger says the alternator is running at 38-62% when the lights blink it drops to 0%.
Think the alternator is going?
Anyone have any thoughts on this?

 

[ridenby]

Its not throwing code?

 

[lbeothuckl]

No code, yet. I connected the reader just to see and its clear.

 

[lbeothuckl]

Just as an update, brought it to the dealership ( I still have power train) they say everything is fine and that the alt is ok.... I'm worried about this and don't buy the "that happens sometimes deal"...
Anyone heard of this.....

 

[Jeepin05]

Yeah I hate that excuse...my theory is "if it didn't do this new from the factory, then something's not right".

I would take it to an auto store like Autozone and have them check the Alternator/Battery for free. The whining is what makes me think the alternator may be temperamental.

Good luck to ya.

Edit: also, how does the serpentine belt look? i think the belt tensioner or one of the pulleys is common to act up on the KJ, might be something to look into for the whining. I'm sure others can chime in with more detail on this...

 

[kb0nly]

Yeah i was going to suggest the belt also... When was the last time your belt and tensioner was replaced?? They should both be done at the same time.

 

[tjkj2002]

You need a DRBIII to correctly test the KJ's charging system and no advance auto or autozone will have one(just the dealership).

 

[kb0nly]

You need a DRBIII to correctly test the KJ's charging system and no advance auto or autozone will have one(just the dealership).

Yep.. That bites..

I think if i ever have any charging problems i will buy an alternator before i go to the dealer, with the service cost i might as well buy one and replace it myself.

 

[lbeothuckl]

I hate that excuse, its completely idiotic. I asked him if they that was in a memo from Chrysler or did he come up with that jewl on his own ( I was in a bad mood !!)
The belt looked fine. I never thought of the belt tensioner... I'll have a look tomorrow. I will have to look up how to replace them, I haven't a clue on that one.
I'm sort of debating whether or not just to get the alternator and put it in, just don't want to throw parts at it..
Thanks for the ideas guys

 

[kb0nly]

The tensioner is an easy replacement, i believe there is a how-to on it here in that section of the forums.

Even if the belt looks "ok" if you replace the tensioner replace the belt too. The tensioner is the expensive bit, the belt is fairly cheap. Expect to pay about $70 for the combo. Then you won't have any belt worries for some time.

You could try swapping the alternator but i know it ***** tossing money at problems like these, especially when the dealer makes excuses. How old is the battery?? You could take the battery and have it load tested and such if its getting old.

 

[lbeothuckl]

I'm going to try and replace the belt and tensioner, if I can get the parts (i'm in a remote part of BC for work. Its a 7 hour drive home to Edmonton so I'm a bit afraid to take the damn thing home.
The battery is new, I put it in back in December of 08 so it should be good.
Could it have been bad gas with water or impurities in it? I'm sort of thinking that it may have caused the problem as it seems to be fine now.

 

[kb0nly]

Well... The best advice i can give is this, here is the thread on changing the belt...

http://www.jeepkj.com/forum/showthread.php?t=34385

I would take the belt off the tensioner and idler pulley and check them for wear and excessive play in the bearings. After seeing a lot of posts on here about them failing i would think if its going out your gonna be able to tell that its worn.

After reading your first post again... Sounds like the alternator output was dropping off when it shouldn't have, hence the lights dimming and the decreased rpm's from the load of the alternator?? I don't fully understand the charging system in the KJ, but i have had what you described happen in an older vehicle and it was usually due to the alternator dropping off under load.

Since you have a 7 hour drive... If you can find an Alternator i would say swap it, but since its also behaving itself now thats a tough call ya know??

How many days or hours before you have to make the trip home? I would say if you go another day of driving and nothing happens it may have been bad gas or a fluke that worked itself out! These intermittent problems are a killer to troubleshoot in person, let alone through the internet.. lol

 

[lbeothuckl]

I just replaced the tensioner, was easy enough, haven't heard anything for noise yet so fingers crossed. I think I may bring it to a reputable garage just to check before the drive. I don't have to make the drive for a week so I have lots of time.
I'll let you know what they say at the garage...
Thanks again for the advice guys really appreciate it.

 

[kb0nly]

Before you get another shop bill, i would just drive it with the new tensioner and belt for a while and see what happens, if you got a week then give it a few days...

 

[lbeothuckl]

Before you get another shop bill, i would just drive it with the new tensioner and belt for a while and see what happens, if you got a week then give it a few days...

Good idea, I'll give er a shot.