Alternator Bad? - Toyota Nation Forum : Toyota Car and Truck Forums

jefe · 01-06-2005, 11:07 AM

I did a search already and found some info. on alternator work, but I am not sure if that is the problem. Can anyone help a noob?

91 4 cyl Camry DX auto. US assembled 3s-FE

I left car outside in MN for 10 days while away for Christmas. (Avg temp probably around 0.)
Came back Monday and it started like a champ. Went on a short trip Monday (20 minutes roundtrip), then 3 more on Weds. On the last trip weds. (with heater fan on High, headlights, and radio on), I turned on wipers and all idiot lights came on on the dash. I turned everything off except headlights & made it home fine (idiot lights went off). Turned car off and was able to immediately restart it.

This morning I went to start it, and could only get a few cranks before it died. Does that mean my alternator is done for? How do I check to see if it is the alternator. (I have a voltmeter but have never used it so I would need really dummied-down step by step.)

That's it for now.

Thanks in advance

CraigW · 01-06-2005, 11:22 AM

With the car running and some loading with lights and fan, the voltage across the battery should be 13.0 - 14.5 volts if the charging system is working.

Pineapple · 01-06-2005, 11:38 AM

Most likely bad battery. The car won't run for long if alt is not working.

McTimson · 01-06-2005, 12:01 PM

Did the lights get dimmer and dimmer on the way home? If it is the alternator that died, then that means you were driving off of your battery alone, so you probably drained it. Charge your battery, check the voltage, it should be somewhere around 12v. Then start the car, and check the voltage again. If it's not at at least 13v, then something is wrong. If it's less than what the battery was when the car was off, then the alternator is probably dead. Try revving the engine, and see how the voltage reacts, if it doesn't do anything, the alternator's dead, if it goes up a little bit, then you've probably got a wiring problem. Clean all your contacts, and double-check all your fuses, the same thing happened to mine and replacing the right headlight fuse fixed it.

To use the voltmeter, turn it on, make sure it's on DC Voltage mode, and if it has the option for display, you'll want it set to 20, I think. Then just touch the red lead to the positive terminal of the battery, and the black lead to the negative terminal. Also, try touching the leads to the battery connectors, if there's a significant difference between the voltage on the connectors and the voltage of the battery itself, then there's probably a lot of corrosion in there.

jefe · 01-06-2005, 03:32 PM

OK. My wife came home at lunch so I was able to jump my car off hers (A Honda Accord

).

I let it run for 20 minutes or so, then turned it off for a few hours. After I read the replies I tested it with a voltmeter.

It tested 13 across before starting it. After I started it and turned on lights/radio/heater fan/hazzard, it tested 15. So, does that mean it is the battery as CraigW said?

(Incidentally, the battery is an Interstate 60 month. Not sure how old it is because the year was never marked on it.)

Thanks Pineapple, CraigW and especially McTimson for the step-by-step. You guys are awesome.

Racer_Rodney · 01-06-2005, 06:47 PM

quick test to see which is bad is to disconnect the Negative terminal while the car is running the car "should" run off the alternator.

or even better, drive to your local autozone and they will test your battery for you, heck they will even take it out of the car (I used to work for them)

jefe · 01-07-2005, 12:17 PM

OK, so I left the car overnight (it was about 7 degreees), and at 7 a.m.this morning it turned over about 1/2 a crank then nothing at all.

I left it until noon, then checked the voltage. Which continued to test at 13v. I tried to start it at noon (temperature about 12 degrees), and it very begrudgingly started.

Can it still be the battery? (I know batteries have to produce cold-cranking amps, not just volts). Can the voltage be okay but it is not producing enough amps. Or, is it more apt to be the starter? Would temperature affect the starter?

Thanks!

Pineapple · 01-07-2005, 12:31 PM

If it won't start its battery. Check voltage while you're cranking. You may get less then 10V.

McTimson · 01-07-2005, 05:42 PM

Yea, sounds like the battery. There could also be something drawing current when the car is off that's drawing all the power from the battery, but I would get another battery first. If the same thing starts happening, then check all the fuses and wiring and stuff.

Racer_Rodney · 01-07-2005, 09:56 PM

Quote:

Originally Posted by jefe

OK, so I left the car overnight (it was about 7 degreees), and at 7 a.m.this morning it turned over about 1/2 a crank then nothing at all.

I left it until noon, then checked the voltage. Which continued to test at 13v. I tried to start it at noon (temperature about 12 degrees), and it very begrudgingly started.

Can it still be the battery? (I know batteries have to produce cold-cranking amps, not just volts). Can the voltage be okay but it is not producing enough amps. Or, is it more apt to be the starter? Would temperature affect the starter?

Thanks!

take it to autozone and have a load test done on it

alxch1n16 · 01-09-2005, 12:26 PM

if the alternator had gone fully, there would be no charging at all. make sure that all of your belts are tight and check for blown fuses and burnt wires. my old saab and porsche both have charging problems now and then and it usually is one of those things causing it. leave the car running and leave the voltmeter on the battery, and if it dips below 13 then most likely it is a lose belt or the battery is bad.