986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Stalls at temperature, only when coming to a stop.

wywyatt · 10-04-2025, 02:16 PM

https://www.renntech.org/topic/47504-troubleshooting-low-voltage-and-charging-issues/#comment-260718/

Followed JFP's advice and did a whole "test everything" according to Ahsai's diagnostic steps at that link above and got a pretty obvious conclusion:
Some part of my alternator is toast!

Alternator casing compared to battery neg - was only .08
Engine Jump point to B+ was .05
Alternator out to B+ was .18
Alternator out to Jump point was .04
Alternator out to alternator casing was 12.85!

I think that's supposed to be 13.5ish. This is with the car fully warmed up, AC max and lowbeams on. Belt doesn't move more than .4". Going to see if I can have my alternator tested; Not sure how to tell if it's my voltage regulator that went faulty or the alternator itself here, but one of them for sure is. It's not the battery because a bad batt can still get up to the right voltage with the engine running I believe.

10-04-2025, 02:16 PM	#19
wywyatt Registered User Join Date: Aug 2025 Location: Georgia Posts: 20	https://www.renntech.org/topic/47504-troubleshooting-low-voltage-and-charging-issues/#comment-260718/ Followed JFP's advice and did a whole "test everything" according to Ahsai's diagnostic steps at that link above and got a pretty obvious conclusion: Some part of my alternator is toast! Alternator casing compared to battery neg - was only .08 Engine Jump point to B+ was .05 Alternator out to B+ was .18 Alternator out to Jump point was .04 Alternator out to alternator casing was 12.85! I think that's supposed to be 13.5ish. This is with the car fully warmed up, AC max and lowbeams on. Belt doesn't move more than .4". Going to see if I can have my alternator tested; Not sure how to tell if it's my voltage regulator that went faulty or the alternator itself here, but one of them for sure is. It's not the battery because a bad batt can still get up to the right voltage with the engine running I believe. Last edited by wywyatt; 10-04-2025 at 03:17 PM.