Is this a dead alternator?

[adnanm3]

I have a 99 996 6spd. For the past few months, it has been a little slow to start. I have to leave the kay to the crank position for 2-3 seconds some times for the car to start.

Tonight after filling up with gas at the gas station, the car would not start. It was making clicking noises and the interior lights were dimming. I got a jump and the car started right up. I did not note the battery charge levels, as I was just focused on getting home safely. In the car, the ABS, traction control and battery light were on. When I was a block away from home, the headlights were weakening and interior lights dimming. The car shut off while I was going 20mhp. Luckily, I was a block away from home and able to push it to the house.

I'm pretty sure the alternator is bad. Any other thoughts?

Right now, the car is not starting. I am assuming it will start with a jump. There is just the clicking sound coming when you try to start it

Also, how difficult is a DIY for an alternator change? How can I tell if my alternator is weak or completely shot? I don't want to go out and buy another battery and have it die in a few weeks.

Does anyone have a link to an alternator DIY?

This is the only ones I could find: http://www.renntech.org/forums/index.php?showtopic=20598

http://www.renntech.org/forums/index.php?s...p;hl=alternator

http://www.renntech.org/forums/index.php?s...p;hl=alternator

How can I tell if I have a problem with the alternator or voltage regulator?

Edited August 16, 2009 by adnanm3

[wross996TT]

So why do you not think it is just the battery? How old is the battery? Do you keep it on a maintainer? Battery is the number one issue with starting a porsche I have found.

[adnanm3]

So why do you not think it is just the battery? How old is the battery? Do you keep it on a maintainer? Battery is the number one issue with starting a porsche I have found.

The battery is only 2 years old. I don't think its the battery because the car shut off while driving 20mph!

I thought that the alternator would keep the car powered if it is already started. Would a dead batteyr have the car die after it was started?

I think it is either the alternator or the voltage regulator. But I am open to suggestions

[adnanm3]

update: I recharged the battery for 5 hours and the car started right up. All of the lights were on on the bottom console. The battery indicator/voltage regulator was reading about 12. When I put the headlights/AC/Radio on, the reading was dropping slightly.

Im guessing it means that the alternator is no good. Before I go ahead and replace that, how can I check to see if the voltage regulator is bad?

[01vdpsc]

Im new to this. I just bought a c4s and left on a family vacation the next day. If you can get the alternator out without too much headache, take it to an alternator shop. They can bench test it and tell you whether or not it is good.

[perryinva]

Normally, if the alternator is good, it would read bewteen 13.75 and 14 VDC while running. A battery test is free at any auto store, so do that and be sure, first. I replaced a perfectly good alternator based on the EXACT SAME symptoms and logic you have and are using. And it was the battery all along. That battery was just over a year old. In general, batteries are the most common source of electrical issues, by far. A faulty battery can easily short the alternator output enough to cause the car to quit running. I thought the regulator was part of the alternator. Rebuilt ones with a core return are not that expensive at all, but it is the install time or labor cost that kills you. All but one bolt is easy to remove, and if you have a pair of swivel universals and a thinwall socket, it is not THAT bad either, suppossedly. ANY work in the engine compartment of a 911 is a PITA. There just isn't any room to maneuver.

[adnanm3]

update: took the alternator out. Found a nice DIY on renntech...not an easy job! The links I posted in my original post were a great help though.

Took the alternator to autozone. They tested it and said that it failed..

ordered a new alternator.

[adnanm3]

Installed the new alternator.

Note: putting it in the car isn't easy eaither (at least its easier than getting it out though!)

Car is running like new again ;)

Thanks for the help everybody

[dphatch]

For what it's worth, the dimming of lights and radio on a car when the engine is running would be the tell tale sign that it was a charging circuit issue and not the battery itself. The only purpose of your battery is to start the car and run stuff like the radio when the engine isn't running and turning the alternator. Your alternator keeps the engine and all the electrics in your car running once it has been started and recharges the battery at the same time.

[adnanm3]

For what it's worth, the dimming of lights and radio on a car when the engine is running would be the tell tale sign that it was a charging circuit issue and not the battery itself. The only purpose of your battery is to start the car and run stuff like the radio when the engine isn't running and turning the alternator. Your alternator keeps the engine and all the electrics in your car running once it has been started and recharges the battery at the same time.

Today right after getting gas, I noticed my ABS and TC off buttons were illuminated...

The battery meter is right under 14 though.. but when I put the headlights on it drops slightly..

Could it be the alternator again?? I'm completely lost..

Edit: The lights went away on their own. Im not sure whats going on..

Edited August 26, 2009 by adnanm3

[perryinva]

I doubt it's the alternator again. In general, though, if you had a bad alternator and the battery drained (more than once) because of it, the battery is never the same. These are not deep cycle designed. The battery does more than just "start your car". The battery supplies instant current when required and regulates spikes, sugres and drops common on a variable rpm charging system. It is more correct to say the car runs everything off the battery, but the battery doesn't deplete because the charging system keeps up with over all losses. Most any modern car can be damaged/suffer issues if run off just the alternator and no battery. I'd be safe, since it's so cheap, and just change the battery.