nwGTS

I mentioned this happened to me once a few years ago and never since. Looking at a few of the questions above... I never run the AC so as a data point of 1, it isn't related to that. It was a hot day here. Again, data point of 1.
The reason I'm posting was something I read about the DFI engine yesterday might add another clue. The injectors actually pulse twice during warm up to get the cats hot. Once in the beginning of the combustion cycle and once near the end. This is also why we get that nice overrun sound while the car warms up. After the cats are hot, the injector pulses only once.

My hypothesis is that since this seems to happen after the car has been only sitting for a few minutes, the engine is hot but the cats might fall below the temperature threshold. So the ECU might be pulsing those injectors twice and flooding the engine as it drops in RPM. Just a hypothesis but my guess is too much fuel being injected causes the flooding and eventual stall as the engine drops RPMs quickly when the car comes to a stop.

Highpox1

If it was a fuel excess, i,e. flooding, rather than a fuel starvation (fuel pump vapor lock), then I would think it would be tough to start up again. Every flooded engine I have ever had takes a while to get going again. Crank crank crank...then finally. When my engine dies, it's always the exact same pattern. Driving for 30 seconds, clutch goes in, then all the lights are on (the engine has died). Immediately turn key left then right, fires up immediately. No issues with restarting. I would say that's not a flooded engine. But you just made me think of something. I have a standard 6 speed. How many of these experiences above are standard shift versus PDK? My engine always dies under NO LOAD, with the clutch in. I wonder if there is a correlation with stick versus auto here... Thanks for the thoughts..

strickrn

My 2009 C2S died at a red light about a year ago and all the lights came on exactly as you described. I turned off the car and it started no problem and I've not had any issues since....?

strickrn

My 2009 is a standard 6 speed. Last summer I was leaving after getting gas and pressed in the clutch approaching a red light and the car died. Turned the key full left and then right and it fired back up. Never a problem since.

strickrn

I searched up the high pressure fuel pump on the NHSTA website using my VIN number and there were 0 recalls for the 2009 Porsche 911 C2S. My vin number is WP0AB29989S720904 and nothing came up. Does anyone have information about this recall? Thanks.

BoomC2S

Not sure if it was a recall a service bulletin or something else, but they replaced mine and I have an 09 C2S.

nwGTS

Good input! Your description of the circumstances matches my experience. I have 6MT. Clutch went in as I rolled to a stop and she died. Started right back up. No repeat in several years.

Canada911S

This has happened to me as well. Picked up my car in August and stalled once coming up to a stop sign. 2011 C2S, 6MT. Nothing since then.

Is hot/humid weather a common denominator for when the stalling occurs?

Highpox1

The temp/humidity definitely has an affect. It never happens to me when it's cool and dry. Always when it's over 70F and humid. I'll bet there is a vapor lock issue between the low pressure fuel pump and the HP pump, and if it's hot, and the car has been sitting a shorter period of time, you get a stall every so often. It clears immediately, and may not repeat for months. Very random. The conditions don't guarantee a repeat. I could never get it to do it at the dealer. The 991 engines I haven't heard of with similar issues. Maybe they modified this..

Balr14

In the old days, when you took your foot of the gas and the car wouldn't idle, you adjusted the carb and maybe the throttle cable. Of course now, that's done for you electronically with a great deal more precision and input from far more sources.... and occasional software glitches caused by a combination of temperature, humidity, air flow sensor readings, engine temperature, fuel pressure, what color socks you are wearing, etc.

strickrn

I'm not sure if humidity is the common thread or not. It's never happened again and I've not tried to reproduce the stall. I'll let you know if it happens and be more careful to document the conditions....happy holidays!

seba

Pretty amazed to always find so much detailed information on Rennlist with a simple google search..
Symptoms I'm experiencing are spot on with what @Highpox1 describes.

Lucky I found this thread as it now seems pointless to try and locate the issue.
Living in Austin, TX so get plenty of warm days.

C2S '09 MT, 73k miles
Recently replaced: Battery, HPFP, spark plugs, ignition coils; so I doubt any of those have anything to do with what we're all experiencing.

MaximumA

Are you all running high flow air filters from BMC or K&N? Once or twice my engine has stalled at the lights, or on a hard stop (in which the revs drop quickly) and my indy tells me that I have excess air flow. which is odd as I have had the filters in there for quite a while...

Petza914

I'm not buying that one at all. You don't have a forced induction setup where air is being forced in - it's being sucked in by vacuum. At idle, the car stops requiring as much air and stops sucking in as much air, so it shouldn't matter what type of filter setup is used in that scenario.

MaximumA

Thanks for this, the issue has me confused and I didn't understand that logic at all. I suspect that my battery might be aging (it's 5 years old), or it's the ghost in the machine.