Alternator gone?

[teevee]

Started my car and it started fine, warmed it up a little bit then went driving. It had a high idle ( in the 2000's ) so I stopped and turned the car off. Checked things out and when I got back in to start the car it wouldn't start. Dash lights would come on but as soon as I clicked it from "on" to "start" everything would shut off, or when I stepped on the brakes everything would shut off including the lights. My AFC was reading 12.6 volts while it was off. Sometimes when I would click it from "on" to "start" the lights would stay on but the car wouldn't turn over. I called a friend and got a jump, the volts were somewhere in the 14's then. Got it home and now it wont start again. I'm guessing it's the alternator but I'm not sure. I checked the MPI fuses and they were fine, and the battery still put out volts.

 

[oldman]

Clean and tighten your battery terminals.

 

[teevee]

I cleaned them but still it has the same problem. Although now it's reading 12.3 volts where as before it was 12.6. Should I opt' for a new battery or a alternator?

 

[versatilx1]

your reading 12.5 from the alternator thats really low its suppose to average 14.5 to 15.5 around there yes get a new alternator but also make sure to check your fuses in the engine bay like alternator choke and etc

 

[Talesin]

And if they're loose, replace the cable clamps. Alternately, you could take a penny, bend it into an 'L' shape, and hammer it down on the screw side of the clamp... obviously after cleaning the post and clamp, just if it doesn't fit tight. That's just a patch job though.

A few GENTLE smacks with a rubber mallet can also seat the clamp tighter, as most battery terminals are tapered. They look like they're on good and solid, but a good thump and the car will start.. only know this because I had it refuse to turn over (and even the dome lights were super-dim with all three on) and the AAA guy just picked his out of the truck, thumped it three or four times, and asked me to try it again. Turned right over.

Then again, I have to replace my own clamps.. when I have a bit of free time.


Also, 14.5 to 15.5 is HIGH, as I've read here. Get your electrical system checked out, man.
It's a 14v system, and it's normal to drop to between 12.5 and 13 while driving, from what I've seen.. the alt is fine. As I understand it, it just isn't constantly charging the battery. But every morning when I go out, soon as I start the car, my Apex'i TT is reading 14v, and slowly drops over the day, never dipping under 12v. And it's back to 14 by the next morning, or if I don't drive it for about five or six hours.
Oh... and it's a brand spanking new alt. Less than 1K miles on it.

 

[teevee]

I got a tip that I should also check the starter ground. How could I go about doing this?

 

[versatilx1]

I was looking in the chiltons manual and if your getting low load current it could be your worn brushes and weak brush springs you might want to check that as for the starter ground, if anything it would be the starter relay you can check the ground here ill take a pic for you ok.

 

[teevee]

Did a more thorough cleaning job on the battery and gave starting it another go, but this time the volts were in the low 9's. Maybe I should buy both a new alternator and a battery.

 

[versatilx1]

wow your kidding yeah man this out of my reach try a new alternator and see what happens if the problem progreses you really need to check it out

 

[EZ91Talon]

Rule of thumb, anything below 13V is low. 9V means that if the battery was not junk before it may be now. To find out:
Disconnect the battery and remove it from the vehicle. Open the caps and refill the cells with distilled water (if it's that type). Put the battery on a trickle charger (1 or 2 amp max) for at least 24 hours. If the battery won't hold at least 13.0V, it's junk. Many auto parts stores will check it for you free if you remove it and take it to them.
Fully charged a strong battery should hold about 13.5V. Get a battery that does, put it back in and start the car.
At high idle (2K RPM) the voltage should rise to 14V (mine goes to 14.3V). If not, your battery is not getting juice from the alternator. If your cables are good (uncorroded and not brittle) and your connections are right, your alternator is probably bad. Many auto parts stores will check it for you free if you remove it and take it to them.
I have a buddy with a Hyundai with a 4G63 and he replaces his alternator at least once a year (just bought the lifetime warranty one). They just keep going bad. I haven't had any problems with mine...Gremlins?

 

[ddavisaf]

Yup Your battery is dead. Betcha betcha betcha.... It's more than likely got a bad cell in it.

 

[mullet]

Not sure if you found your problem or not, but I've had lot's of alternator problems with my car. My factory one went and I replaced it with one from a local parts store (auto value) becuase it had a five year warranty. We'll I've gone through 2 of them (when the car gets hot it's like the alternator can't keep up and the voltage drops on the AFC to below 12 volts.

I was getting weird stuff like the coolant light, battery light, and park brake light coming on when the voltage was low (apparently it was feeding back through the system). Also my compustar does weird stuff when the voltage is low (like the relay goes on and off when the car is running and you step on the brake). I had the car checked out at the dealership, and they said it's just a crappy alternator.

I've just placed an order for this high output alternator hopefully it is of better quality:

http://www.4alterstart.com/pages/st...p://www.4alterstart.com/highoutputalternators

Stock amps is 75 for us model and 90 for canadian. This one is 135 amps.

One more thing, I'm running a 2g manifold and 02 housing so I didn't bother to use the lower heat shield. Since the dealer said it was making the alternator too hot I modified the heat shield to fit, and that seemed to help the problem (it takes longer for the car to start loosing volts). Hopefully that'll buy me enough time until I get my new alternator.