Jeep YJ Squealing low voltage and trouble code Advice

hunkajunk · Nov 28, 2007

Had that annoying squeaking belt. Just put on a new one last weekend. While I had the belt off I spun each of the pulleys and they moved freely. Drove it Sunday for 100+ miles no squeak no problems.

Tuesday it starts squeaking again. Only the sound is different. Less rubber squeal and more fingernails on a chalk board metallic sound. I checked the belt tension and all bolts on the tensioner (all fine). Sprayed on belt dressing and thought the squeal was gone. Not so. It only happens when I'm in gear and above idle.

So today on the way home from work squeal starts up again and I notice the voltage is reading unusually low. Turned off fog lights heat and defroster then the voltage went back up to 14 and squealing stopped for a bit. Then the idiot light comes on. Pulled the codes when I got home code 47 "Battery voltage too low and alternator output too low"

Checked my chilton manual and several web resources. It sounds like the alternator but could it be the battery as well. Opinions.

What kind of damage am I likely to do if I drive it until the weekend?

Thanks!!

skrause · Nov 28, 2007

Voltage regulator?

hunkajunk · Nov 28, 2007

I'm pretty sure it's built in the alternator. If it was separate the regulator would be much easier to change in the dark and rain.

JOOP · Nov 29, 2007

replace your altenator.

They always start to squeal when they die. I can't remember the price of a new one but its not too bad on the wallet., about $100 or so. If you get one from one of the loca parts stores get one with a lifetime warranty. Because the YJ alt's dont like mud. Which reminds me, mine is squealing too.

hunkajunk · Nov 29, 2007

Thanks JOOP :beer::beer:

Now the next question is stay with the stock 90 amp or jump up to a 140 amp in anticipation of more electrical accessories. Or is that way overkill?

Cascade_Crawler · Nov 29, 2007

I never had a problem with my stock one...

hunkajunk · Nov 29, 2007

Cascade_Crawler said:
I never had a problem with my stock one...

Cool. More pennies left for other parts.:redneck:

Will I destroy anything if I drive it to and from work until the weekend?

JOOP · Nov 29, 2007

never had any issues with the stock 90amp. Just try and keep it dry.

The only thing thats going to get destroyed is the alt, if you drive it everyday. But if the alt isn't putting out atleast 12 volts, then your going to be draining your batttery. You wont get very far for very long on battery life. Maybe a day or two if your lucky.

Oh wait EDIT: Maybe your battery too. depending on if it'll take a charge after being drained. Some stock or cheap batteries call it quits and die too. If you have an optima you should be good.

skrause · Nov 29, 2007

hunkajunk said:
Cool. More pennies left for other parts.:redneck:

Will I destroy anything if I drive it to and from work until the weekend?

the belt. :haha:

What I meant earlier is since it spins ok your voltage regulator must be trying to get too much out of it and your belt is slipping. Is it tight enough?

JOOP · Nov 29, 2007

skrause said:
the belt. :haha:

What I meant earlier is since it spins ok your voltage regulator must be trying to get too much out of it and your belt is slipping. Is it tight enough?

Oh yeh belt is a possibility too, but only if you alt seizes up. The noise your hearing is probably the bearings saying thier last words. :redneck:

hunkajunk · Nov 29, 2007

skrause said:
the belt. :haha:

What I meant earlier is since it spins ok your voltage regulator must be trying to get too much out of it and your belt is slipping. Is it tight enough?

I'm think it's tight enough. I've got about 1/2 inch of play in the longest span. I don't have the tension meter tool critter to check it with. A buddy of mine who's had a number of CJs checked the tension and gave it the ok.

JOOP · Nov 29, 2007

yours has a tensioner pulley. It tightens itself.

hunkajunk · Nov 30, 2007

UPDATE:

Autozone tested the alternator and gave it a pass.
Got a dying cheap hygrometer and checked the battery - pass. At least all the balls floated to the top per the instructions :eeek:.

Put everything back together and tightened the belt a bit tighter then it was before. No more squeal. :cheer: But With all the accessories on, when I'm stopped and at idle the jeeps volt meter drops to 12 ish and lights dim.

Voltmeter on the battery reads:
12.5 engine off
14.6 engine idle no accessories on
13.8 idle with radio, heater, defroster, hi beams, fog lights, and brights on.

Checked as many grounds as I could find in the dark. I haven't done a load test on the battery yet. Taking it to Autozone after work tomorrow.

Even though the battery tests to date don't look terrible, could my battery be dying?

What next? :scratchhead:

Edit:
There is no regulator on my jeep. It's controlled by the computer.

skrause · Nov 30, 2007

hunkajunk said:
Autozone tested the alternator and gave it a pass.

Depends, did the vatozone flunky have a clue what they were doing with the tester? :haha: What's the chance that the brushes are worn, how old is it?

hunkajunk · Nov 30, 2007

skrause said:
Depends, did the vatozone flunky have a clue what they were doing with the tester? :haha: What's the chance that the brushes are worn, how old is it?

Guy seemed to know what he was doing. Not that I would know the difference :haha: but he didn't fumble around or look lost.

I haven't a clue how old it is. I bought the jeep a year ago. it's a Denso (sp) 90 amp. I don't thing it's the orig.

The wife is starting to pester me for buying a piece of junk.

:booo::haha:

Would it be worth swapping in a new alternator or should I get a new battery? Can't afford both at the moment. :redneck:

TreeClimber · Nov 30, 2007

hunkajunk said:
Put everything back together and tightened the belt a bit tighter then it was before. No more squeal. :cheer: But With all the accessories on, when I'm stopped and at idle the jeeps volt meter drops to 12 ish and lights dim.

Not uncommon in my experiences. Too low of RPM for the alternator to be putting out much juice, so you're basically running off the battery, and it show's 12ish. When you rev it up, voltage goes to 14ish, and lights brighten up. Alternator could be 'weak'. Maybe the bearings are starting to go, maybe not. Maybe the internal regulator is starting to go, maybe not. I'd run it for a while and see.

Of course, in my case, I'd make sure I had jumper cables. Just in case.

hunkajunk · Nov 30, 2007

TreeClimber said:
Not uncommon in my experiences. Too low of RPM for the alternator to be putting out much juice, so you're basically running off the battery, and it show's 12ish. When you rev it up, voltage goes to 14ish, and lights brighten up. Alternator could be 'weak'. Maybe the bearings are starting to go, maybe not. Maybe the internal regulator is starting to go, maybe not. I'd run it for a while and see.

Of course, in my case, I'd make sure I had jumper cables. Just in case.

Yup we keep a set of jumper cables in all of our vehicles. It only takes getting stuck in an inconvenient place once to become a believer.

Thanks for the help.

I'll run it around town for a while. Any trips to the hills to play in the snow are out until this gets sorted out :eeek:.

skrause · Nov 30, 2007

TreeClimber said:
Maybe the bearings are starting to go, maybe not.

If bearings were going out tightening the belt would make it worse.

skrause · Nov 30, 2007

hunkajunk said:
should I get a new battery?

It's not your battery.

JOOP · Nov 30, 2007

here's what you do.

Once the jeep starts squealling at idle, pop the hood, get a can of WD40, spray the alt if the squealing goes away theres your problem, if it doesn't spray the tensioner pulley, if it goes away theres your problem. Just dotn spray the inside of the belt.