Damn Cobra!!! Help

[360Rocket]

So I'm taking the wife to dinner and then a Xmas party and the damn "battery" idiot light pops up on the dash of the Cobra. Thankfully the car doesn't leave me stranded and I get to meet my 3rd tow truck driver in 2 weeks.

Now help me remember the trick...I disconnected the positive battery terminal
and the car kept running...that would be a bad battery, correct?

thanks gang,.

[DevilSun]

I think you've got it right, I think it's the battery at that point. I'd wait to hear from someone else though because I don't have full trust in me agreeing with you.

[D ROUSH]

Is it just me .. or does this ROUSH cobra need to stay in the garage .. garage time.....

[roushstage2]

Yeah. If it dies, it's the alternator.

[GlennF]

Originally Posted by 360Rocket

Now help me remember the trick...I disconnected the positive battery terminal
and the car kept running...that would be a bad battery, correct?

Ummm, no. that isn't a "trick". That was the old shadetree method of seeing if your DC generator was working back in the 50's. It is highly recomended to NOT DO THAT on a modern car that uses an alternator. You are risking creating a voltage spike that may damage integrated circuits or other solid state devices.

There are procedures to check the alternator, integrated regulator and battery to determine why your charge light is coming on. If you aren't sure on how to do them it would be best to leave the testing to a trained professional.

[360Rocket]

Well I had 12.5 volts on the battery when I got up this a.m., ran the car and it jumped up to 14 volts. turned on A/C, lights, stereo, etc, and it dropped to 12.5 volts.turned off stuff with engine running and it went back up to 13+ volts. BTW, no battery idiot light either. WTF?

[crexrun]

Might be a stuck brush in the alternator, or simply not making good contact. Could be the alternator, if you've never replaced it, might be a good time to anyways. If it had 14 volts running, it's obviously charging...however, is it ALWAYS charging? Take the battery and have it load tested, doesn't take much time at all...maybe there's a weak cell in a battery, and it's GOT 12.5 volts static, but as soon as theres a load, that cell drops out. Try the battery first. Good luck, Justin

[roushstage2]

Originally Posted by 360Rocket

Well I had 12.5 volts on the battery when I got up this a.m., ran the car and it jumped up to 14 volts. turned on A/C, lights, stereo, etc, and it dropped to 12.5 volts.turned off stuff with engine running and it went back up to 13+ volts. BTW, no battery idiot light either. WTF?

I know it's kind of an idiot suggestion, but are the terminals and posts clean and tight? I have had my truck not start because of the above a few times.

[360Rocket]

Originally Posted by roushstage2

I know it's kind of an idiot suggestion, but are the terminals and posts clean and tight? I have had my truck not start because of the above a few times.

this car is spotless at all times.

[GlennF]

Originally Posted by 360Rocket

Well I had 12.5 volts on the battery when I got up this a.m., ran the car and it jumped up to 14 volts. turned on A/C, lights, stereo, etc, and it dropped to 12.5 volts.turned off stuff with engine running and it went back up to 13+ volts. BTW, no battery idiot light either. WTF?

System voltage should not drop below ~13.5V while running. Battery voltage when fully charged should be 12.6V, to keep it charged your alternator has to put out voltage higher than battery voltage under all operating conditions or the battery will go dead. It could be a low output alternator or a shorted cell in the battery draining the system. My money would be on the alternator being the culprit since the battery held voltage overnight. A bad cell will usually kill the battery after it sits a day or two.

[D ROUSH]

I am with Glen on this one.. but could it be a loose belt? what am I doing posting in a "whats the problem thread"

Hope it fires up bud

[wavgby]

Randy, I had the same problem, It started like yours I failed to do anything cause my light went out then It wouldn't start one day I jumped it and to it to autozone for a free load test and the battery had a bad cell. All of this took a couple of months from light one day to replaceing the battery. Autozone can test both the battery and the alternator at the same time for free and only takes a couple of minutes and they test them on the car. Pep boys down the street from where you work on 60 can do it to.

[2blowncodds]

Check the water in the battery.

[360Rocket]

Originally Posted by 2blowncodds

Check the water in the battery.

its good, I check all fluids once a month.

[13 MIKE]

this car is spotless at all times.

Except for the molasses stains.

[360Rocket]

Originally Posted by 13 MIKE

Except for the molasses stains.

yeee hawww, yuck a yuck a yuck. Thanks for the backup from a fellow GTO owner....

[13 MIKE]

Your Mustang is cooler than mine, and your Goat is prettier than mine, hows that for backup.

[360Rocket]

Originally Posted by 13 MIKE

Your Mustang is cooler than mine, and your Goat is prettier than mine, hows that for backup.

They are all just cars man, all just cars.

[360Rocket]

It was the alternator, another $400 I didn't have to spent.

[zlynxs]

I think this is a sign that you should just sell the slobra to me