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. Theres no other reason for the car to shut off while driving. Any other thoughts?
Right now, the car is not starting. I am assuming it will start with a jump. Battery seems very weak, but I think the alternator is the problem.

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.

 

You could confirm this before spending a lot of money by simply charging the battery. If your car returns to 'normal' for a while, then it says your alternator is not working well enough to keep the battery charged. At that point, remove the alternator and take it to a auto parts store and have them test it. Most will do this at no charge.

 

Mileage? How old is the battery? Have the battery checked first. Easy to do...just take it to an auto store and they will check it for free.

 

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?

 

Most likely your alternator. You can try a durametric reader to get your charging voltage in real time. It should be around 13.4V or a little higher.

FWIW, your charge voltage should read above 12, almost to the 14 mark actually with nothing on. If you imaging a clock face, it would be the hour hand at about 10:30.

If your engine is relatively new (compared to the car) you might actually have a bad wiring harness rather than a bad alternator. Over time, the corrosion will reduce charging efficiency and make it look like a faulty alternator.

-td

 

Don't jump into conclusion about the alternator. I had the same
symptoms and it turned out to be the battery. Voltage reading
under 12v. Everything pointed to the alternator until I has it checked.
Alternator was fine... Then I had the battery checked...it turns out that
the battery had bad cells.
Have the battery checked....easier than the alternator.
Good luck

 

The easy way to find out if it is battery or Alternator. 1.Start car 2. Pull positive battery cable off the battery. If car instantly dies, Its your alternator!!!!

 

Actually it's the negative cable... This is old school testing method... Warning: Do NOT do it this way. You have chances of damaging your electronics..ecu, etc. Use a volt meter or drive it to an auto store and they can check it for you..

 

Stop making this rocket science........ When it is not.. I hate when people do this. Pull the neg or pos off and if car shuts off, its alternator. If it stays on, it's the battery or there is something wrong with your charging circuit relay, that up can buy from dealer. You have a chance of blowing your cars engine when you drive it everyday too.... DUDE. Please dont put variables out there that will not apply. Voltage spike...(anything over 14-15Volts, be very worried) Voltage drop, it will not hurt any ecu or mechanics. IT WILL JUST SHUT OFF!!! I am just giving the guy some insite. I have done alot of aftermarket and mechanics around porsche cars. If worried, turn off all eletronics (Radio, aftermarket amps, etc. )and then do it. It will remedy the problem in 2 seconds. I rebuild Porsches and design aftermaket systems for Aston martin's DB9 eletronics, Ferrari 430 and 348, Vipers...... I think know what I am talking about. But it is
up to you............................

 

update: took the alternator out. Found a nice DIY on renntech...not an easy job!
Took the alternator to autozone. They tested it and said that it failed..
ordered a new alternator.

If anyone wants DIY info, it can be found here:
http://www.renntech.org/forums/index...howtopic=20598
http://www.renntech.org/forums/index.php?s...p;hl=alternator
http://www.renntech.org/forums/index.php?s...p;hl=alternator

 

I know it's pain in the *** job. And you mite as well change out the accessory belt if the original one has some miles on it. That's why i told you the quickest way to find the problem. But I am glad you figured out its the alternator. Because thats what it sounded to me when you first posted the problem.

 

Installed the new alternator.
Note: putting it in the car isn't easy either (at least its easier than getting it out though!)


Car is running like new again
Thanks for the help Immanuel and everybody else

 

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...not sure whats going on.

 

Any update on this ?

 

Any updates on what is causing your alternator to keep popping?
mine did the same thing. my alternator got wet and it started lighting up to the dash. got it rewinded and changed the voltage regulator and after clearing the fault codes,when I hit 100km going home to lights flickered twice then stayed on(psm/airbag and exclamation points) and the voltage meter went down. I wonder whats wrong