Two months ago my alternator was showing signs of going bad so I had it rebuilt by the shop the Porsche dealer uses. I did the R&R on the alternator. All was well for two months.

Yesterday I stalled the car taking off on a steep hill and quickly restarted the car. The battery warning indicator came on and the voltage gauge showed less than 12 volts. Got it home and let it sit overnight.

This morning I put a external meter on the battery and it showed 12.2v. I then started it and the meter showed 13.8. Let the car run for 30 minutes and all showed OK. I then stopped and started it a couple of times and on the fourth or fifth start, same thing, meter showed 11.4-11.8 volts. Stayed that way for couple of minutes. Shut it down and started up again and back to normal. I did this several times and every once in a while it will act like not charging and the next time, back to normal.

I really hate to R&R the alternator again as it's a bit of a pain but I don't trust the way it's acting.

Any ideas of what could be causing this intermittent problem?

 

I talked with the shop which rebuilt the alternator and they asked if it was getting a control signal? Not sure what that means or how to test?

I do recall two connections on the back of the alternator, one heavy duty cable and the second a much smaller gauge.

Any thoughts on this control signal being the cause of intermittent failure after some starts?

 

The control signal is the smaller connection.Your base voltage readings are a little low-should be in the 12.7 range which could indicate just a bad batt or a result of faulty chg. system.Simple things to ck would be ths serp. belt condition & tension & if the smaller connector terminal pins are spread,corroded etc & don't forget about the batt. term's as well.

 

Also check the grounding strap from the battery jump spot in the back to the frame.

 

Where exactly is the grounding strap from the battery jump spot located? Thanks