Alternator OR Battery problem????? (HELP)

[disel78]

Okay here is the deal I have a 89 S-10 Blazer 4.3 liter with a fair amount of miles but anyway so I drive here an there around town this weekend nothing major, but tonight I take off stop get gas notice nothing and off to the highway. Not even 2 min on there I notice my battery light comes on and my dash lights get dim my windshield wipers slow down…. I have my stereo on which I have a system and amp and all so I shut it off right away. Then I had the defrost on, so I turn it off to, look at my battery gage and it’s at like 9 amps. I think it’s normal at 14 amps I have no idea what is normal although. But yea when I came to a stop I had to rev it up cause it would act like it was going to die. The alternator was replaced or rebuilt like 4 years ago and I have a big as die hard in there which is like 4 or 5 years old. So yea what do you think it may be?? It was weird it just happen out of no where. I keep my battery well maintained and stuff so I don’t get this?? Any ideas??

[wolfox]

Sounds like you have nearly all of your windings out on your alternator. Most likely two out of its three phases. Time to swap for a rebuilt/new again. But before doing so, check a few things and do it RIGHT:

Replace battery cables and install new hardware after brushing the places where they bolt to on chassis and starter motor. Brush the battery terminals clean too and charge the battery for at least 6 hours on a 10 amp charger, periodically checking electrolyte level. If in six hours there is no drop in electrolyte or fizzing, leave it overnight. Use a turkey baster to top off the battery cells that are low with *distilled water* only. Check battery voltage after charging - half an hour later. A fully charged battery with no internal faults will read 12.5~13.8 volts. And if you do not have one, get at least a half-farad capacitor for your bins in the back. Running big power on subwoofers hammers the sh*t out of your alternator and its regulators. If you are pushing more than 650~700 watts on your bins, consider a full, 1 farad cap or larger. It will keep you from eating up alternators and drawing heavily from the battery. Remember: Your alternator is only there to maintain a charge on your battery, your battery giving the muscle needed to run electrical accessories.

[BlazerLT]

Alternator is dieing.

Replace it and charge your battery separately up to its proper level.

DO NOT EXPECT THE ALTERNATOR TO CHARGE THE BATTERY, IT IS NOT A BATTERY CHARGER.

[Rmbodie]

You guys are up late too , Before replacing anything check your ground wire that may be bolted to the thermostat housing . On my 89 ,it broke and the battery died because of the voltage drop not because the alternater was bad . I can wiggle it and the volt meter in the dash is effected ,Rob

[wolfox]

Originally Posted by Rmbodie

You guys are up late too

Sleep is for the weak! Night time, when it is not raining is when I catch up on the stuff here and beat the bugs out and do maintenence on my truck. There will be plenty of time to sleep when I am dead.

[mike2004tct]

Originally Posted by Rmbodie

You guys are up late too , Before replacing anything check your ground wire that may be bolted to the thermostat housing . On my 89 ,it broke and the battery died because of the voltage drop not because the alternater was bad . I can wiggle it and the volt meter in the dash is effected ,Rob

A good idea to check all connections before replacing anything, but......

A bad ground will not cause the volt meter to raise linearly when accelerating the engine. A bad connection would cause the meter to behave erratically. I agree with most of the other posts, it sounds to me like a bad alternator. Get a hold of a volt meter and check the output at the battery (12.5V min) and right off the alternator output terminal. Alternator should be above 12.5V at idle.

Dirt knaps, huh?

[BlazerLT]

Actually, at idle, the alternator will put out 14+ volts.

It is the amperage goes up as you raise the rpms.

[disel78]

Originally Posted by BlazerLT

Actually, at idle, the alternator will put out 14+ volts.

It is the amperage goes up as you raise the rpms.

Thanks for all the tips guys, I will chack all conections and what not but as far as charging the battery and checking volts and Amps and all that stuff I just don't have the tools for it. I am a college stsudent with a old Blazer pretty much just trying to get it to work. I have heard of going to like Shucks or Kragen or whatever it is and or Autozone (GRRRR..) and they have a tetster is that a okay thing to do or is it just bullshit, otherwise I will just go to a shop once i know what I am dealing with and have the aternator repalced. I got out my paper work from when I got it replaced back in 2000 so I am hoping 5 years is a good run have no idea the life of a alternator, just hope driving for like 20min last nite on it with it messing up didn't fry my battery I had no chice I had to get home anyway let me know what you think later.

[BlazerLT]

Don't trust the alternator test at the stores, they do not subject the alternator to the engine temperatures that cause it to overheat and fail.

Replace the alternator yourself. It is so easy!

[riccbhard]

Yep. Alternator is probabaly dying. This happened on my aunt's 1998 Blazer LT. Alternator has been replaced but every now and then the lights will still flicker but very rarely. We were just driving along and the battery light started flashing, volt meter measured 6 volts. Everything died. Replacing the alternator solved the problem. I've notcied though that after the alternator has been replaced there is a whirring noise coming from the front of the car.

[BlazerLT]

Originally Posted by riccbhard

Yep. Alternator is probabaly dying. This happened on my aunt's 1998 Blazer LT. Alternator has been replaced but every now and then the lights will still flicker but very rarely. We were just driving along and the battery light started flashing, volt meter measured 6 volts. Everything died. Replacing the alternator solved the problem. I've notcied though that after the alternator has been replaced there is a whirring noise coming from the front of the car.

You should look into that.

You probably overadjusted the alternator to have the belt too tight.

The whirring is probably stress on the alternator bearings.