Is my alternator going out?

[Looger]

So, I got out to start my Bronco II, and it's dead. So, I jump it, drive for about 10 minutes, come back, turn it off.
I assumed this wasn't far enough to charge it, and sure enough, the next day I needed another jump. So, I drive about the same amount of time, and once again I don't have enough juice to start it again.

Now, I figured that since I didn't drive all that far, my battery just didn't have enough time to charge, but something kind of worrying happened on the way back the second time. The battery light came on as I was driving back, and all the lights on the dash and radio were flickering.

Now, normally I would go out and test it myself, but my volt meter and other tools and whatnot are 100 miles away. Also, I know parts stores will test it for you, but I just want to see if anyone can tell based on my description.

If the alternator going bad, I'm hoping it will at least last long enough to drive back to where all my tools are...

 

[adsm08]

Sounds like it to me. From what you have described I would not try to drive it 100 miles. Not unless you get your battery charged up to full potential and take a few spares.


Just remember, your fuel system, your ignition system, and your engine control system all need electricity to work at all. No juice, no running.

 

[Looger]

Balls. Well, this is going to be tricky without any tools...

Also, if I were to start it up, and test the voltage on the dead battery, would it still read 13ish with a good alternator?

 

[adsm08]

13 is weak but acceptable. It should run but won't charge the battery very well. I usually try to sell alternators when the run below 13.5V.


Start checking for loose wires. And start with the big ones. Battery cables, ground straps, and the big boy on the alternator.

 

[Looger]

There is quite a bit a corrosion and what not built up on the battery, I'm just figuring out what the worst case scenario is, what with me not having any tools and all.

And I haven't actually tested the alternator, I just wasn't sure what the voltage should be. Currently I don't have access to a voltmeter.

 

[doorgunner]

you kin ruin a good alternator with a bad battery.....and ruin a good battery wiff a bad alternator.....and spend a LOT of money because of corroded wires...

but i've never did anything like that myself.......bawling

 

[4.0B2]

clean the cables.. completely.
charge the battery, and have the alt checked..

but my bet is on the alt.

 

[Twister]

Could be voltage regulator.

 

[adsm08]

Could be voltage regulator.

And have you tried to get a regulator for an 87 by itself lately?

They just don't sell them except for attached to an alternator.

 

[Twister]

And have you tried to get a regulator for an 87 by itself lately?

They just don't sell them except for attached to an alternator.

No i haven't, i have only dealt with the 2.8L. Autozone sells one that is different than the one for the 85 and it claims it is for an internally regulated alt.

 

[adsm08]

No i haven't, i have only dealt with the 2.8L. Autozone sells one that is different than the one for the 85 and it claims it is for an internally regulated alt.

And then there is so much BS to deal with. Besides, by the time the regulator is shot the whole thing is probably done for anyway.

 

[mp3deviant721]

My truck does this from time to time. And when I read that the battery and cables are corroded and you need to get it jump started, I'd say first clean the battery and cables. Then try starting it. Mine does this and when it doesn't want to start, I clean the cables and presto, it starts. Mine also makes a whining noise from the speakers that changes with engine RPM when it acts up. I've done a VAT test on my truck too. The alternator tests out good and the battery is ok.

 

[Twister]

And then there is so much BS to deal with. Besides, by the time the regulator is shot the whole thing is probably done for anyway.

True.

I'd get both the battery and alt tested .

 

[RustedRanger]

When my alt "went out" I got a regulator for mine,it was overcharging. I think it was Car Quest that had it. They also had a new coil plug in that no one else carried.

 

[adsm08]

When my alt "went out" I got a regulator for mine,it was overcharging. I think it was Car Quest that had it. They also had a new coil plug in that no one else carried.

But yours was over charging which does indicate a bad regulator.

It sounds like his is undercharging or not charging at all, which is more likely worn out brushes. Easier to just replace it.