Dead battery after driving

[twostar]

Got a 99 Ranger, V6 3.0L.

Had a dead battery this morning, I last drove it on sunday and didn't leave anything on afterward. I got a jump from a neighbor which frankly surprised me that it even worked. I drove it to work and noticed an oscillating noise from the radio that was linked to engine speed. Once at work I check the battery voltage with the engine still running and got 13.3V at the terminals. I turn off the engine and get 12.8V. Try starting the truck and it won't turn over, voltmeter reads 10v.

I've had some problems with starting this truck recently, see http://www.explorerforum.com/forums/showthread.php?t=222808 . I had the same problem listed in that thread at the beginning of Oct and ended up bringing it to a shop since i had no time to work on it. They diagnosed it as bad batter clamp to cable connection due to corrosion. They clipped and stripped the end of the cables and reconnected the clamps. Been working fine until today. I had the battery checked by them and by schucks and les schwab. All declared the battery fine then.

Reading through the forums here it seems bad cables are a good chance but would they still deliver 13.3V to the battery if they were bad? Would it just not be enough amps to charge the battery or discharge back to the starter? If that was the case then why did jump starting it work?

Going to have the battery checked at lunch since it's under warrenty still. Anything else to check/do before calling the shop back for more work?

 

[BrooklynBay]

Clean the terminals, and apply an antioxidant cream.

 

[twostar]

terminals look clean and clamps are tight. They got a thorough cleaning at the shop a month ago and only minor corrosion since then. I will pick up some anti-corrosion cream though.

 

[gnzth01]

A sudden occurance of alternator whine usually means your alternator has decided to die. Rectifying diodes are probably shot... If you can, the best thing would be to take the alt off and bring it in to just about any auto parts store. Most will test it for free.

Get the battery charged and tested too, they like to fail together. A bad alternator can kill a battery, then the pretty much dead battery will take out the new alternator.
A battery that sits at 10V can also mean a bad cell, as there are (6) ~2.2V cells in the battery. So when when goes bad, you'll see about 10 volts at the terminals.

 

[twostar]

It's sitting out in my office's parking lot right now. How long of a process is it to remove the alternator? I've got access to tools here and there's a NAPA down the street.

Would a bad alternator explain not taking a jump start?

 

[lrlima]

i took my wifes car to an autozone after her battery died to make sure the alternator was charging okay. they hooked a machine up to the alternator while it was still in the car and could tell if it was charging the new battery ok.

 

[marragtop]

13.3 volts at the terminals with the engine running, seems too low. This could be due to bad cables or a bad alterntor. Try testing the volts at the alternator connection(if you can get to it), not at the battery. Your problem with it not always taking a jump is probably jumper cable connection related. Depending on how good the cables are, sometimes you have to move them around to get a good connection.

 

[gnzth01]

It's sitting out in my office's parking lot right now. How long of a process is it to remove the alternator? I've got access to tools here and there's a NAPA down the street.

Would a bad alternator explain not taking a jump start?

Honestly, I don't know. I have an '04 Exploder, and I've actually never even looked at the alt.

 

[gnzth01]

i took my wifes car to an autozone after her battery died to make sure the alternator was charging okay. they hooked a machine up to the alternator while it was still in the car and could tell if it was charging the new battery ok.

Doesn't really tell you much, other then there's a problem. Could be a problem with battery, alternator, or cables. If it's not too much trouble it's best to to just isolate every thing.

 

[Tbars4]

...Testing the charging system via the crash cart usually leads to false information...As mentioned before, take the alt and battery out and have them bench tested for a proper analysis...20 minutes or so to remove and the testing could be up to an hour on the battery and about 5 minutes on the alt...

...I am definately not a fan of adding cable ends as it is a newly added source for a bad connection....You may also find that your battery cables are corroded within the sheathing which is a common problem...Your charge reading should read about 14.3...

 

[TheJackal]

I'd say alternator as well.

If the battery is dead and the alt isn't good, there may not be enough power to run the control module, and so jumping won't work anymore.

 

[twostar]

Just talked to the shop and they said they've gotten it to start right up each time they try. They checked the charging system (alt, batt, cables) and that all checks out. Going to run down to the starter and check that path. Now I'm thinking an intermittent starter problem. If they don't diagnose it with something reasonable by tomorrow, I think I'll swap cables and starter this weekend myself and see if that solves it.

 

[marragtop]

When you get the no start situation, does it crank or click at all, or does turning the key to start have no impact? If it has no impact try starting it in neutral (I'm assuming it's an AT) and try the brake pedal in different positions. Just a long shot....

 

[twostar]

most of the time when I try starting, the dash lights dim like there is a power draw but the starter doesn't kick over or click. The one time I was able to jump start it i got the normal clicking sound from the starter indicating a drained battery.

I've tried shifting the transmission from park to neutral and it doesn't help. I've had problems in the past with the transmission park sensor and this actually seems like it's trying to start rather then a switch preventing it.

I haven't tried playing with the brake pedal however. A long shot but easy to play with.

The shop called me back later and they can't find anything wrong with it. They're going to try starting it again in the morning to see if something is different but sounds like I'll have it again without any real diagnosis.