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How Do I Find Out If My Alternator Is Going Bad?
mean_04_focus
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UBB12-ML-2417187187-ML-
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Well, go get a multimeter. I'll wait for you to get back.
Okay. Turn the meter to DC voltage. Put the black wire on the negative terminal of the battery. Put the red wire on the positive terminal of the battery.
Make note of the voltage level. It sould read somwhere around 12.5V
Start the car. Repeat the above. It should read somewhere around 14.0-14.4V. If it does not, then your probably have a bad alt or maybe just a loose connection somewhere.
This test is not infallible, but it is a good place to start. Take it to autozone or something and have a load test done. That's the real way to do it! :thumbup:
Okay. Turn the meter to DC voltage. Put the black wire on the negative terminal of the battery. Put the red wire on the positive terminal of the battery.
Make note of the voltage level. It sould read somwhere around 12.5V
Start the car. Repeat the above. It should read somewhere around 14.0-14.4V. If it does not, then your probably have a bad alt or maybe just a loose connection somewhere.
This test is not infallible, but it is a good place to start. Take it to autozone or something and have a load test done. That's the real way to do it! :thumbup:
1) Insert Key (do not turn it)
2) Press and hold the Trip-Meter Reset Button
3) While holding the reset button, start your car and continue holding the button.
4) Within 10 seconds, the display should change to "test" (written in a silly LCD font) and the needles will go nuts. No biggie. Release the Button.
5) Pressing the button will now cycle through some 15 different modes.
after pressing the button about 15 times, you will see a lowercase b with 3 numbers after it. that is your battery voltage. at startup, yours should read 14.0 or higher. if you have an underdrive pulley, it will be a little bit lower(13.8). if it's lower than this, you are about to be in trouble.
2) Press and hold the Trip-Meter Reset Button
3) While holding the reset button, start your car and continue holding the button.
4) Within 10 seconds, the display should change to "test" (written in a silly LCD font) and the needles will go nuts. No biggie. Release the Button.
5) Pressing the button will now cycle through some 15 different modes.
after pressing the button about 15 times, you will see a lowercase b with 3 numbers after it. that is your battery voltage. at startup, yours should read 14.0 or higher. if you have an underdrive pulley, it will be a little bit lower(13.8). if it's lower than this, you are about to be in trouble.
Hey I just went through that test and was getting 13.8-14.00 without turning on the stereo or A/C. I have a UDP, diablo chip (which I just yanked before doing this test), a system using two rather modest amps, and a FS CAI. My battery got killed a few months back and was covered in corrosion. I mean, I was picking the stuff off with a knife, and wound up covered in green dust and shavings when I was done. It took a lot of work to get the car running again, due to wear on the battery terminals.
Well, from then on, I would very occasionally get the battery light to come on, though it was always after wide open throttle on the freeway. It would then quickly go away. I figured the diablo was cheating power with the battery and alternator.
But today my battery light started coming on and staying on half the time. My car stalled and stopped at an intersection, though it started up with ease. I have that mild issue with the fan not turning on at idle with no A/C as well, though I'll get around to it someday. I had a long drive home and the battery light just would not go away. I tried going at 3/4 throttle in lower gears but it would sometimes come back on anyway. I checked my battery and terminals and there is (surprisingly) no more corrosion. I can't figure out what it is, though I suspect battery cables. Any other suggestions? Is there any way out of going to the shop first thing in the morning?
Well, from then on, I would very occasionally get the battery light to come on, though it was always after wide open throttle on the freeway. It would then quickly go away. I figured the diablo was cheating power with the battery and alternator.
But today my battery light started coming on and staying on half the time. My car stalled and stopped at an intersection, though it started up with ease. I have that mild issue with the fan not turning on at idle with no A/C as well, though I'll get around to it someday. I had a long drive home and the battery light just would not go away. I tried going at 3/4 throttle in lower gears but it would sometimes come back on anyway. I checked my battery and terminals and there is (surprisingly) no more corrosion. I can't figure out what it is, though I suspect battery cables. Any other suggestions? Is there any way out of going to the shop first thing in the morning?
So far the shop said I needed a new alternator. They determined bad diodes after their test. Well, I got my car back, and it ran for a few hours until the battery light came back on. I took it back and got it tested, and they said it appeared ok and told me to come back the next morning. While driving away, my car died. No power left
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I've burned out 2 alternators so far (JRSC heat) and each one made a short high-pitched squeal when the car started just before it went, similar to belt noise. I know it's not the scientific way to tell but if I ever hear that sound again I know what it is.
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I did find a way to fix the issue - I scrapped the whole JRSC! It's not that it wasn't fun to drive, but now I'm going turbo. At least that's my solution. (I know, I know...the turbo will produce heat as well, but not in the same immediate location and I'm getting a vented F2 hood)
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Fortunately, there is no law that says you must follow your own advice - I'd be a lifer in the supermax wing if there were.
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I've started my hatch before and taken the battery completely out, as in not connected at all. It ran fine.:dunno:x714x said:
My battery was dead and since I didn't have jumper cables I took the batt. out of an escort and put it my focus, started my car, took the scorts batt. out and replaced it with mine. The car ran the whole time. You can disconnect the battery while the car is running and not have it stall, provided the alt. is putting out enough juice to keep it going.
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