Punko

Took the 911 out for a long drive today.

Unfortunately, after about an hour of driving multiple warning lights turned on. Battery, PSM/ABS, Check engine....eventually, just the battery light remained on.

Warning notes "generator failure", "brake distribution failure".

Voltage looked to be at around 13V.

I decided to drive back home. The voltage reading slowly decreased from 13, to 12, 11, 10.5 then quickly dropped to 10.

At 10, multiple warning lights turned on again. Battery, PSM/ABS, Check Engine, Air bag.

Luckily I made it back home and was able to open the frunk and engine compartment.

I turned the car off and it would not start, no more juice.

I am thinking it could be alternator, regulator or wiring.

Any suggestions as to cause?

Thanks.

993GT

Mark, sounds like alternator to me.
If you want, if you are able to charge the battery and think it will make it to Brantford, I'd be happy to help diagnose
Cheers,
Rob

Carlo_Carrera

Yes, sounds like classic alternator or regulator failure. Luckily both are housed together in the alternator. Replace the alternator with a new one and shoot two birds with one stone.

A good test is to remove the battery from the car and fully charge it. Take it off the charger and let it sit on a table (not on a concrete floor) and periodically check the voltage over a two day period. If the voltage stays constant over that time the battery is probably good. Then stick it back in the car and drive around with as many accessories on as possible and see if the battery dies. If it does you most likely have a bad alternator or regulator.

If you are feeling adventurous Pelican does sell just the regulator which can be replace by taking apart your existing alternator. Good luck.

Punko

Thanks, appreciate your offer.

Charging the battery.

Not sure how to tell if alternator or regulator.

Car has 90000 kms (56000 miles)

Punko

If the battery was bad would the voltmeter gauge read less than 12 to 13 while running?

993GT

in my experiences with alternators(various car makes/models), typically it is the brushes/regulator that fails.
Do you have a handheld voltmeter? Should be 13+Volts when running to be happy. A half decent OBD2 scanner will also have an alternator test function. If all this fails we can scan with my Durametric and/or do further hands-on tests.

996tt cracker

try auto zone advance auto napa they can run a scan just did it on my truck bad diode

Punko

Is there a way to test if it is the alternator or regulator with the alternator still in the car?

rmc1148

A shop can check battery and also do a load test to check charging system. They will not I believe be able to tell you its the regulator specifically.

Punko

11.78 Volts at idle.

jpflip

Tooo low…..It should be over 13.5 at idle. When you start cold it should be above 13.8 and sometimes 14 and when the engine is warmed it should stay above 13.5 even if you load it with lights , a/c, fans etc….Suggestion: save yourself lots of money , start by changing your voltage regulator! Easy job to do once the alternator is on a bench. There is a lot of DIY for alternator removal on different forums….

rmc1148

Agree with jdflip.

PorscheDoc

Yup changing a lot of VR's in turbos lately. $30 regulator is much cheaper than a new alternator!

jpflip

Good to see you around Doc! Thanks again for your blog, we learn a lot from it!

Kevinmacd

Your regulator went, you can just buy the regulator, and save some money.