dspill

Hello.

I've experienced the following symptoms recently and it seems to be getting more frequent:

Situation: 2010 Carrera is fully warmed-up after being driven 15-30 minutes. I stop the car. After a short (~5 minute) stop I restart the car with no trouble. I pull away with no noticeable symptoms but as I come to the next stop sign, as I'm applying the brakes and slowing down the engine dies completely.

I can quickly restart the engine and there are no further symptoms or occurrances from that point.

It's happening more frequently now (total 4 times). The outside temperatures are getting higher so I'm suspicious this is heat related because it's happening after an engine heat soak. There are no codes thrown or pending in the OBDII at this point. Car has 94,000 miles (YEA!).

Any ideas? I haven't tried to recreate this on purpose but that's my next step once I have some idea what parts to focus on.

DC911S

You probably need to datalog to hunt this down.

JAGMAN1

It could be the throttle body needs a cleaning. Modern engines adjust the opening of the throttle body to adjust idle speed relative to temperature and load. In hot weather the a/c puts significant load on the engine at idle, if the throttle body were binding even just a little it could cause the symptom you describe. It's a cheap thing to try before you get into more significant trouble shooting. Just make sure you buy oxygen sensor safe cleaner. I'd clean it and see how it works. Next step would be a throttle adaptation procedure and read codes.

Macster

Based on the behavior my WAG is a fuel pump has to be suspect #1. IIRC there are two fuel pumps a low pressure unit and a high pressure unit. While the high pressure unit comes in for all the publicity the low pressure unit can go bad and cause problems.

The problem is with the intermittent behavior which one -- if any -- do you replace? I can't say. There may be a way for a Porsche tech to ID which one is acting up and therefore which one should be replaced before the unit fails outright and leaves you stranded.

I would at least explore having a professsional make a diagnosis. My concern is if the low pressure fuel pump is acting up the high pressure fuel pump may have insufficient fuel supply and pressure to operate properly. This could lead to the high pressure fuel pump being damaged as it relies upon the fuel for cooling and lubrication of its moving parts.

Misdirection

I wish someone would figure this out...

Has been brought up before.

I have experienced it in my car since it was relatively new, but it has been extremely infrequent/intermittent. Although it has happened twice this calendar year. I have had the dealer and independent shops investigate but nobody can ever figure it out. There are no codes. One thing I wonder is if it might be related to the ignition switch in the dash, but I have not done anything to test that.

dspill

Misdirection:
Wow, thanks for the new info. I am sort of glad to hear another one, and that it's not fatal yet. I have access to a good data logger and someone who may be able to read it so I'm going to try to recreate this and see what I find. I will update as I learn more.

I also thought about the ignition switch. I have tried to wiggle it a little to recreate the occurrence but haven't had any luck. The ignition switch is a bit odd as it sometimes clicks as soon as I insert the key and sometimes it doesn't.

I also experience slow cold starts after the car sits overnight - 5-8 seconds turning over. Car turns over fine, it just take a longer time to fire up. I don't know if they are related but it's another potential clue.

Bruce In Philly

I suspect it is related to fuel delivery.

Regarding your "click" please describe more.... when you remove your key, do you always get the "clunk"? If you do, your wheel will lock of you turn it... if no clunk, the wheel will turn freely subject to tire friction of course. If you do have this, it is not the ignition switch but another software problem. I had this random no clunk thing and swapped the ignition switch out... did nothing.

By the way, these ignition switches in the 997.2 are not like the older ones... these really are just a rotary button that turns on the ignition radio. I really believe they are keyless systems retro'd to be a key turning thing. I dismantled the "faulty" ignition switch 'cause I am a geek, and there really is nothing in there like the traditional ignition switches.. just a thin-wire coil. really a simple unit and hard to believe anything can go wrong with it.

Peace
Bruce in Philly

Stanisl0ve

Hate to revive an old thread, but have you had this happen again or have you solved the problem? Happened on my 2010 C2S yesterday, for a second time during my ownership (1 year).

Thanks much

Highpox1

I have had this problem in my 2010 C4S for 6 years now. Even when it was relatively new. The pattern is the same. If I am stopping for < 1 hour, and it's warm outside (75+F), when I start it up and start driving off, there is a 20% chance the engine shuts off in the first 60 seconds. Not every time, but I would say one in five it does it. I push in the clutch, reset the key to the left and restart- no problem, fires right up. No codes. The dealer has no idea why. Sometimes I go months and nothing, then it will do it 3 times in a month. Weird.