When will the Alternator go?

[LibertySport]

Hello dudes/dudettes,

Ol'girl is throwing the battery light. It stays on for about 15-20 seconds then shuts off for about 3-5 minutes.

Just noticed driving on my way to class. I know the battery is in good shape. The battery is getting replaced anyways with an Optima.

The alternator is going bad but I need it to last until the weekend till I can pick up the part?

What are my chances of this happening? Is this just warning indicator notifying me to replace soon like a CEL before it starts blinking?

Should I be stressing about it now or not? I planned on replacing it at 120K anyways. I'm at 115K right now so I guess 5K before scheduled replacement is alright haha.

Thanks for the help and information.

 

[M38 Bob]

What's your daily mileage? Sounds like it's gonna go soon.

Bob

 

[LibertySport]

3 days a week 15-18 miles on class days. The other two days 3-5 miles, to the train station and then back home.

But I have to put about 25-30 miles this weekend I have test at 0930 for my job. The location is about 11.5 miles away from my house.

 

[Jbergun]

Yea if your theowing a battery light means voltage got pretty low and if it is a pretty new battery there is no reason for that. My jeep lasted a day after i threw a bat light. I ran my voltage all the way down to 6 volts befoee she shut down on me while driving. Got a charge and made it the two miles to my house. Died as i pulled up to my spot not easy parallel parking without it running.

 

[CzarKJ]

Better to tackle it now before something bad happens and leaves ya in the middle of nowhere. Or at least pick one up and put it in the back seat with a few wrenches.

 

[tommudd]

Have it tested before you say it needs replaced
Think again on the battery you mentioned as well, used to be good, anymore more towards the bottom of the pile

over 217,000 on mine

 

[LibertySport]

I'll tackle it tomorrow or Thursday. Should be a pretty quick swap.

Thank you for the help.

Any recommendations for replacement?

Looking at this right now: http://shop.advanceautoparts.com/p/...4-P?navigationPath=L1*14920|L2*14999|L3*15587

 

[Jbergun]

Thats what i did remanned with a warranty is the best bet. Do you have any extra power pull auxiliary lights or a sound system if so get the liberty rubicon alternator its 160amps if i remember correctly.

 

[adamkrz]

Old mechanics trick is hit it slightly with a hammer and watch it come back to life..Really.

 

[TwoBobsKJ]

Thats what i did remanned with a warranty is the best bet. Do you have any extra power pull auxiliary lights or a sound system if so get the liberty rubicon alternator its 160amps if i remember correctly.

I think you mean "Renegade" alternator. You're right, it's 160 amps but if the Liberty didn't come with it from the factory then it won't do any good to up from the 136 to 160 amp version - the BCM is set at whatever alternator amperage it came with from the factory.

Best bet is to replace with exactly the same amperage unit as it had new - otherwise just spending more money that won't realize any benefit. :shrug:

Bob

 

[tjkj2002]

Old mechanics trick is hit it slightly with a hammer and watch it come back to life..Really.

To bad the voltage regulator(which that trick is for) is not in the KJ's alternator but in the PCM.

 

[renegade 04]

Well If you want to add the 160 amp alternator just add a external voltage regulator like I did when my internal voltage regulator in the ECM went bad. Also A good Idea would be to get a voltage gauge so you can monitor any problems with the voltage as you are driving.

 

[Billwill]

You could wire your Multimeter into the front power socket/cigar lighter and monitor the voltage as you drive...see if it drops as the charge light comes on.

Bear in mind that the early KJs have a battery Temperature Sensor mounted under the battery to monitor battery temperature and adjust the charging accordingly...if this sensor or its wiring malfunctions then it also sets the "charge" light although the alternator could be fine. I had this happen to me...bad wiring coming from the battery temp sensor.....check for codes, a bad temp sensor sets a certain code which I cannot remember at the moment!

First thing is to have the Alternator and battery tested though!

 

[Jbergun]

Thats what i meant renegade but i thought that was a viable upgrade from a regular limited or sport alternator. In my case i would get it because i dont have amperage problems it just stresses the 136amp alternator that i have. So if i put in a 160amp and it only pulls 136amp it should be able to handle it better. Then again i am probably wrong i dont know about this stuff. Not sarcasm i really dont know much about this stuff.

 

[Jbergun]

What tomm is saying optimas are not as good as they used to be

 

[tommudd]

Thats what i meant renegade but i thought that was a viable upgrade from a regular limited or sport alternator. In my case i would get it because i dont have amperage problems it just stresses the 136amp alternator that i have. So if i put in a 160amp and it only pulls 136amp it should be able to handle it better. Then again i am probably wrong i dont know about this stuff. Not sarcasm i really dont know much about this stuff.

Wouldn't make any difference, not worth the money if you have to pay extra for the 160, its not going to run easier, better or anything

 

[tommudd]

You could wire your Multimeter into the front power socket/cigar lighter and monitor the voltage as you drive...see if it drops as the charge light comes on.

Bear in mind that the early KJs have a battery Temperature Sensor mounted under the battery to monitor battery temperature and adjust the charging accordingly...if this sensor or its wiring malfunctions then it also sets the "charge" light although the alternator could be fine. I had this happen to me...bad wiring coming from the battery temp sensor.....check for codes, a bad temp sensor sets a certain code which I cannot remember at the moment!

First thing is to have the Alternator and battery tested though!

Or just run a Scangauge like I have for the last 9 years, tells voltage and a whole lot of other things

 

[TwoBobsKJ]

Or just run a Scangauge like I have for the last 9 years, tells voltage and a whole lot of other things

Tom, is your Scanguage pretty accurate when it comes to mpg's? I know my EVIC is off by a couple of mpg's at least but if the data is coming from the same source I've wondered about any improvement in accuracy.

Of course, there's always the old fashioned way - doing division at each fill up - but that's so 1980's, ya know...? :happy175:

Bob

 

[Jbergun]

Wouldn't make any difference, not worth the money if you have to pay extra for the 160, its not going to run easier, better or anything

Good to know i havnt had any problems with my second remanned but i stopped pulling as much power. I dont want to have problems. Now i run a measly 700wrms@ 4ohms. And i usually have a system voltage of 13.7-14 volts in the heat. Winter time i do a little better 13.8-14.2.

 

[k99jk99j]

To bad the voltage regulator(which that trick is for) is not in the KJ's alternator but in the PCM.

true about the voltage regulator, but in the past this trick works on my externally regulated denso alternators, i assumed it was freeing up the 2 brushes that were making intermittant contact, which it sounds like what the o.p. alternator is doing?