Stalling when warmed up and extended cranking time to restart

Hi all, New to the forum and still new to 996 ownership but had a problem come up yesterday. I've got a 2003 996.2 tiptronic with 90k miles. The problem came about that when the engine was fully up to temperature, when I came to a stop at a set of lights the engine just cut out. No roughness to any indication, it was just as if I turned the ignition off. When i tried restarting the car, it wouldn't fire up as normal, as 1-2 seconds of cranking, but needed to crank for maybe 7-10 seconds and then slowly started to run. By this, it wasn't the usual immediate fire up but cranking then would gradually start to fire and then run. When it was then running, even though it was at warm running temp, the car would idle higher like it does on a cold start, around 900rpm and could feel the extra pull when holding the brake when in D. If i turn the car off with the key, it will then crank as normal and start but still run the idle as if it is cold. It happened three times after this on the same with the same issue of high revs and long cranking after it cut out. No issues with power delivery but didn't push the revs too hard. After getting home, left the car for a couple of hours and went back out. no issues starting from cold, the engine had the cold idle revs then settled down as normal, but after maybe 25 minutes of running, it cut out again, and same issue of long cranking and high cold start idle. No smell of fuel or any warning lights on the dash, but haven't had any codes read to see if anything is pending to report. Going to get it booked into a garage to look at but wondering if anyone has had anything similar to help point to where the issue may be coming from. Thanks, Joseph

I had exactly the same thing today for the first time on my Turbo.

These may help: Starting issues - replacing alternator "Y" cable I've been experiencing starting issues for a while, but they all seem to stem from "something else" - starter motor, alternator and battery have all been replaced in the past few months with new genuine Bosch items I got stranded in a supermarket car park at the end of December after a short... 911uk.com Slow starting issue has reared its head again, positive lead So I thought I had got away with my slow starting issue, it had been fine for a while and was starting up easily hot or cold. I spent a week in the Alps and had a couple of hot starting moments again but it does always start up. It is just very slow on the first turn of the starter and then... 911uk.com

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Thanks sp1ke. Looked at both of these threads when searching about the issue but the symptoms aren't matching. There's no hesistation in the cranking power when turning it over and no issues if I turn the car off and start it again with the key. The problem only happens when trying to restart after it stalls, along with the problem of it stalling and then the cold start idle revs.

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I'm starting to wonder if it could be the collant temp sensor due to the cold idle when restarting after a stall, possibly the ecu thinking the car is cold?

Could be the crank sensor, they start to play up when they get hot so can cause stalling and hot start problems.

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would there be a way to check on this without replacement? Would there be a diagnostics reading for the sensor values?

They don't always throw a code if it is intermittent. You can test the sensor with a meter by checking the resistance, although I can't remember what the figure for this is when it is hot/cold etc?

If the temperature sensor is reading incorrectly then you will eventually get a fault code thrown. It might take several drives and weeks though as the problem worsens. The temperature gauge will suddenly drop to zero and illuminate red. Scary, but not serious. You will also get the fault 'cooling system performance' or 'failure indicator' which means that the temp sensor signal is out of range. These are the two common faults when a temp. sensor goes bad. It's an 8 pound part and relatively easy to change out.

this as well Porsche 996 slow cranking Many owners of Porsche 996's will have encountered or will encounter at some point the problem of slow engine cranking. The symptoms will be slower than normal engine cranking when cold and exacerbated when engine hot. Typically this will be sluggish cranking when first starting the car in the... 911uk.com

Hi, I had this issue. The fuel pump was suspected as likely but when tested, it was fine. In my case, it was horrible. Searched the engine and couldn’t find any issues upon my Indy checking. Turned out a rident had bitten a wire on the loom. Engine and box out job and I replaced everything possible before it went back in. The symptoms sound just like mine. I hope yours is simpler. On the plus side, the car drives incredibly now

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Thanks Menace, hoping it's not as horrible as this. Will get the garage to take a look and test to see if they can discover the cause

Update on this. It turned out to be the crankshaft position sensor that was at fault. Narrowed it down luckily as I had my code reader in the car when one of the stalling and then the first occasion of it refusing to restart, not start the longer cranking to fire up. The reader flagged that the sensor was at fault, accompanied by the tacho needle not moving at all. The strange thing is that the ECU was not storing the code in memory after the event and being able to restart. Ordered the sensor and had it fitted a week ago and so far no issues at all. Not to say that this will cure everyone's issue if they experience the same symptoms but worth checking with a code reader if it stalls and won't restart. The part was only £50 for a Bosch sensor from GSF and about an hour and half to fit (much easier if the sensor isn't stuck in due to build up). Thankful that is was this and thanks to everyone for their help and suggestions. Next jobs are replacing the exhaust clamp due to a slight leak and the engine mounts as the driver side is starting to sit lower

My money is on the camshaft solenoid, I tried all sorts to sort this out, but it kept coming back to this solenoid, it’s a big job, can involve dropping the engine to do a proper job, can be done in situ but more difficult to ensure you get the sealant right. Are you getting a code? Mine was showing P1341. camshaft adjustment. Bank 1

It was the crankshaft position sensor that was at fault. Can't remember the code it threw up on the reader when I was able to get it to but it translated to the crankshaft sensor.