LemonDrop

Hi,

Anyone have any ideas? ...

Very intermittently, like days, can be when stationary and idling, or leaving a traffic light, or at highway speed, the engine stops running, the dash lights all light, and then go normal. If when idling, I just need to turn the key clockwise and it starts right up. If it happens when moving, it restarts on it's own, seemingly from the car's momentum.

Replaced the crank angle sensor and the battery at the dealer. Not fixed.

Can't reproduce on demand in any way. Dealer says can't reproduce, can't fix. Nothing logged in the ECM.

Car runs perfectly before and after that instant. Starts perfectly. Cold or hot, no matter. Bumps, swerves, stops, acceleration, can't get it on purpose.

Any one see this before?

Here is a screen shot from video capturing it. I recorded every driving moment for 2 weeks to get this when it happened.

Arrrggghhhh.



Moment engine cuts off.

Michael_s

Crank sensor. Just came up last week. Good luck.

LemonDrop

Thanks for the reply. As I mentioned the crank sensor has been replaced already. Any other thoughts?

guab

Wow, that's super weird. How many miles can you drive it before it happens again? If you can nail it down to that delta, it might be easier to have the dealer reproduce it.

LemonDrop

Totally (seemingly) arbitrary. No predictable mileage interval, time interval, conditions. Went 2 weeks nothing, then 3 times in one week, but a day or more apart.

I'm starting to look towards voltage. I'm usually in sport mode where the voltage rides up to 14.5 maybe even higher. It did it once at startup on a cool day in normal mode where the temperature had the idle up to 1300 or so and voltage up to 14.5 ish. And I think in most cases it happens in sport mode. I am now staying in normal mode to confirm if it does or doesn't do it.

I understand 14.5 ish is typical for Sport mode, but I wonder if it's takes excursions higher for some reason, like alternator?, can that cause this? 14.5 V is quite a bit higher than the expected 12.6 V battery volts, independent of charging status.

Michael_s

My apologies. Reading on my mobile and didn't see that part. Good luck with the fix.

Need4S

Sounds like an ignition switch issue or the interface with the stop/start system.

sdg1871

That might be the throttle body/oil separator it happened to me

LemonDrop

Like this:

https://youtu.be/friKRQpUI30

?

sdg1871

Never mind happened when I was pulling up to a light or sitting at a light not when I was pushing on the gas

DaveChapin

This happened to me about 10 times last winter. Happened while idling at a stop lights. Very annoying. I had the local Porsche dealer see if they could find anything amiss, and after a day, nothing. It hasn't happened to me for months. But, it's now winter again, so I wonder if the stalling will resume.
[maybe it just happens to yellow cars]

LemonDrop

It does it then too. Totally random. Those are just two I caught on camera. Warm, cool, slowing, idling, arbitrary. No rhyme or reason.

NiteJav

Turn the stop start system off, maybe there is something going nuts there....

LemonDrop

​​​​​​First thing we looked at. It's always off, I don't like it. The Christmas tree wouldn't light. Thanks.

worf928