Car question (alternator)

[calamari]

alright, I have a problem with my gf's car.

it's an 91 escort and has an almost new battery (a few months old).

after sitting for like, 2 1/2 days, it refuses to start.

cause: battery doesn't have enough charge. (is not like the lights or anything was left on).

I asked for a jump, and after I got it running, the guy who helped me said that it might be the alternator, and to prove it he pulled the negative (black) cable from the battery while the car was running... and it stopped.

he said that if the alternator was working fine, the car would continue running.

Is this true? do I need a new alternator?

thanks. car's and me don't mix  

[coll0412]

I asked for a jump, and after I got it running, the guy who helped me said that it might be the alternator, and to prove it he pulled the negative (black) cable from the battery while the car was running... and it stopped.

Most newer cars don;t run if you remove the neative cable, your 91 may or may not be new enough but that is not a valid way to test your altenator.

First thing I would do is take the battery to the place I bought it, first to check if it is bad, and to get it charged. The more time you have to jumpstart the battery the shorter its life.

Second, if it turns out not to be an alternator, get a digital multimeter and hook it up the batttery, you should read like 12.7 Volts with the car not running, thjen start it up, hook your meter back up and look at the reading, it should read like 12.7 or so, less than that==bad, then what you want to do is turn on all the loads onthe electrical system(i.e headlights, blower motor, windshield wipers, radio..) check the voltage, it should still read about 12.7V or maybe a touch less, then rev the engine to about 3 grand and hold it there, look at your meter it should clime in tho the 13V range, no change and you guessed it, no charge is getting to the battery. This doesn't neccesarly mean a bad alt, just that the bat is not getting the charge. You can repeat this test but put your leads from you multimeter on the main post of alt, and a ground point. If you get the same results odds are its your alt.

If you want to save some time, drive it up to like Autozone or Shucks,Kragen, Checker and they can test it.

In my personal opnnion if the car sat for like 2 days then didn't start, but before that it would start regualy, I would guess a drain in the system somewhere. IF you think it is that I will explain also how to test this also.

[Blazinjr]

My clock on my radio will drain the battery in my Neon if it is not started or drove in 5 days, but I also have a garden tractor battery in it.  There is not enough room in there for my full size battery.

In your case check and see how much your alt is charging.

Also is there any stereo amps in your car or anything else other than standard equipment that is hooked up to your GF car?

[NightRyder]

Er, take it somewhere that will test it for free. = Sure fire way to know whats up.

It could actually be the battery. Is it a cheapie? Even if not, you wouldn't be the first to get a lemon instead of a battery.

[calamari]

yeah, thanks. I've called to autozone, and they do test batteries and alternators for free (i think).
my best guess (and worse situation actually), is that the alternatos is bad.
You see, since a few days ago, whenever my gf let go of the accelerator (stop light), the engine would idle irregularly... as if the engine wanted to shut down. but she never tells me anything wrong with the car, until it goes dead  :x

btw, no stereo equipment or anything extra.

any guesses on what a shop may charge for replacing the alternator? (the alternator itself is like $100 at autozone).

[Roadstergal]

Slap a multimeter on the battery and start the car.  You should see a charging voltage - 13ish.

If not, work from easy/cheap on up.
-Battery terminals.  Clean and secure.
-Connection of alternator to electrical system.  Clean and secure.
-Alternator to ground.  Clean and secure.
-Alternator belt.  If it slips, you won't charge.  That can happen if the belt is old or the tensioner is out of whack.
-Voltage regulator.  It has brushes that wear with use.  It's on the back of the alternator.  You can solder in new ones easily.

Alternators go bad much, much less frequently than one of the above happens.

[natedawg120]

yeah note to you, that test is for older cars.  The way the charging systems and stuff work in newer cars like your gf's ford pulling the cable like that could have adverse effects on the computer controls for ignition and emissions.  Normally it doesn't but i wouldn't do that cause those things are freaking expensive.  Take it to the parts store and have them check it out, if it is neither it could be a couple other things but it prob is the alt if it wont hold a charge.

[Roadstergal]

any guesses on what a shop may charge for replacing the alternator?

Too much.  Especially as it's unlikely that the actual alternator is toast.

[Phaedrus]

...the guy who helped me said that it might be the alternator, and to prove it he pulled the negative (black) cable from the battery while the car was running... and it stopped....he said that if the alternator was working fine, the car would continue running....Is this true? do I need a new alternator?

I've seen this test done and have personally used it and found it to be generally true. I haven't tinkered with a 91 Ford Escort, but I am sure it is not that difficult to do. I've installed an alternator in a Dakota and a Status. It is easy enough to do yourself provided you can get to it without too much of a problem. I think if you and a friend that knows how to hold a wrench wanted to give it a shot, I think you could do it. ESPECIALLY if you have a shop manual, but even if not I am sure you could do it    A shop would probably cost atleast $300+ or more (rough estimate).

[natedawg120]

Yeah esp for a ford around that year.  They always wput two different alts on thier little cars so if you are lucky you have the not-so-espensive on to replace.  Shop ballpark, probably around $300-$400 if you are lucky

[Alphamazing]

I'd say that if it is the alternator you should install it youself if it needs replacement. It'll teach you a lot about how your car works. I had to replace a clutch on my Civic. It was a dirty job, required partially dropping the engine as well as taking out the transmission housing. It was grueling, long, tedius, frustrating, dirty (I got an oil bath at one point), and well worth it. I learned a lot and saved $300. I was lucky enough to have a mechanic telling me what to do (I did the work myself) and a car lift, but yours should be easier. Go for it, if you need to!  

[calamari]

well, this case is solved.

it turns out it wasn't the alternator  
the alt was outputting the right amount of volts, however, the battery wasn't.
in fact, the battery had only some 110amps out of 500 for cold start  

I assumed that the problem was caused by those feminine battery connectors I bought some time ago (the ones you can plug and unplug with your bare hands), so after i bougth a new battery, I went ahead and bought a pair of manly connectors (the ones that have  screws and stuff) and placed them really tight with my metal-made and heavy wrenches and stuff.

Still, the guy in the store told me that another problem could be the cables themselves. i don't know.

it's an old car that my gf got for free anyway :lol:
thanks everyone for your input .