Charging problem...and advice needed!

Millerad1651

Millerad1651

New member
So hopefully some of you guys can help me out. A few days ago, I noticed a humming from the engine bay. There was a slight vibration in the brake pedal, but only while in park or drive at idle...it went away as soon as I accelerated.

Then this morning, I headed to work. 2 miles later, radio started turning on and off. Then the battery light and ABS light came on. I got abut a mile from work (8 miles later) and it completely died on me. Got a jump, and drove it to work. Thinking it was the alternator, I changed out the brushes (read a lot that these were the main problem). Jumped it, letit run for a while, and headed home. Got home with no problems. Then once I turned the truck off, I couldn't get it started again. I would think that the alternator would charge the battery up enough on a 20 minute drive. My Ultragauge was reading 11-12 volts at around 1500 rpm. I have the trickle charger on it now, seeing if the battery will even charge.

Could it still be the alternator? I would think that since I got home, the battery was getting a charge strong enough to keep the truck going, but not enough to start it. I plan n yanking the battery in the morning and taking it to get tested...it's less than a year old. Anyone have any other theories? Sorry for the long post, electrical sh*t pisses me off!
 
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11 or 12 volts isn't enough to start and your alternater isn't charging enough !. Good luck sir should be around 14.5 running
 
id look at grounds and wires... look for lose connections. you sure you plugged in the harness back into the back of the alt... ive forgot that before and felt dumb...
 
Ha, ya I double checked my alternator connections. I cleaned up the terminals and threw some dielectric grease on there. The bearings were good, the pulley rotates smoothly. I'm beginning to think the battery is bad if it won't take and hold a full charge.
 
Perhaps the rectifies (diods) or the IC (very rare case) has gone bad. Can't you find a used Denso alternator at a local junk yard? I personally don't rely on any aftermarket (remanufactured) alternators as they pump about 13.8 V without a load and with a load it will drop to 13.2 V.
 
Checking the charging system with a bad battery isn't accurate... Start with a known good battery... Alternator gets my vote though
 
A crude test would be to use a MM and see what you get, aiming for nothing less than 12.3v from the battery itself.

How old is the battery?

Remember, heat kills batteries. I don't know hot it has been in the Hoosier state this summer.
 
So I had the battery on a trickle charger all night last night. Got up this morning, started right up. It was showing 14+ volts. I got a couple miles down the road, and the volts had dropped to high 11s, low 12s. I decided not to chance it and came back home. Turned it off. I started it again, and it started right up. Grabbed the wife's runner and headed to work. I plan on taking both the battery and alternator to have them checked, and will grab a MM at work to bring home.

The battery was a year old as of mid June. It has a 3 yr free replacement, so easy fix if that's it.

The alternator was easy to work on. Taking the battery out makes it so much easier to pull the alternator. I cleaned it up well, and changed the brushes...about 2 hours start to finish.
 
Battery sounds fine, it seems to be a charging issue for sure.

Added any electrical add-ons or such in the last ten to fifteen days? Any mice or rodents in the engine bay? Check your wire connectors as well as the wire running to the ALT. All grounds as well. Check your ALT relay by the battery?
 
Alternator. You can confirm 100 by pulling the neg. terminal off the batt while the truck is running. If it dies then the alt is bad. Easy to pull the alt and have it tested too

Regardless of the strength of the battery you should be getting 14.2-14.7 volts on the terminals from the alt.
 
I started it up after sitting all day, started right up. Put a MM on it, registered mid to high 13s. Then I pulled the negative post off the battery, and it kept running. I kept it running for a few. Turned it off, then restarted...fired right up. Anyone have specific locations for checking out grounds?
 
I had a charging & dead battery problem for several years (not as serious as yours) until I finally did the Big-3 and everything was fixed.

I even have a spare Toyota alternator I bought on eBay for $65 but never used.

It is highly recommended to replace the chassis to battery negative with a thicker wire.

My Big-3 ugprade link (pg. 20) -----> http://www.toyota-4runner.org/3rd-g...-build-maintenance-thread-20.html#post1357810


In the picture below it is the lower rightmost 4G wire.

 
clund21 said:
Alternator. You can confirm 100 by pulling the neg. terminal off the batt while the truck is running. If it dies then the alt is bad. Easy to pull the alt and have it tested too

Regardless of the strength of the battery you should be getting 14.2-14.7 volts on the terminals from the alt.
Click to expand...

I was always told this is a very BAD idea. A quick Google shows I'm not the only one:

http://www.troubleshooters.com/dont_disconnect_battery.htm

It won't cause a problem every time, but it's a risk not worth taking.
 
dont rely on an alternator to charge a battery. thats not its job.
and infact you can kill an alt with a badly discharged battery.

use a trickle charger to be safe.
 
TheDurk said:
I was always told this is a very BAD idea. A quick Google shows I'm not the only one:

Don't Disconnect the Battery with the Engine Running

It won't cause a problem every time, but it's a risk not worth taking.
Click to expand...

Oops. Well fortunately for me none of those things happened...I'll keep that in mind in the future.

nevada said:
dont rely on an alternator to charge a battery. thats not its job.
and infact you can kill an alt with a badly discharged battery.

use a trickle charger to be safe.
Click to expand...

I used a trickle charger all night last night. I just watched to see if the alt would keep the battery charged and how many volts the alt was producing.

So I think changing the brushes and cleaning up the alternator worked. I've driven around 10 miles and let it run for 10-15 minutes, and the volts are staying up. CLund was probably right that the brushes have to break in. Plus my battery was most likely fully drained from jumping and running three times yesterday and didn't fully charge on my trip home.

I plan on eventually doing the big 3 wire upgrade as well. Thanks for all the help guys.
 
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