First time the Boxster has let me down at an event
 

Two day event. First day - everything was fine. Wife and I shared the car - no hiccups at all. Did have a couple times when it was cranking but didn't want to start but did.

Next day car fires up fine several times before the first session. First session of the second day - second lap - front straight - shift into fifth and the engine shuts off. Felt like I turned off the key. Wouldn't restart. Towed in.

Since it's on Motec - I'll have to dig into the ECU and see if I can see anything. Looks like the info from the dash says fuel pressure was good even when the engine died so I'm thinking it's ignition related.

First inclination is crank position sensor. We shall see.

Oh and then I head home early and well my trusty Q7 decides to die on the road home while towing. Looks like I had a boost leak. Pretty cool they could tow the car and the trailer. Not cool that I had this happen all in one day.......

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Ok was able to pull down the data from the ECU. Looks like the crank sensor (REF sensor on the motec system) and a bad Lamda Sensor - which is the 02. Just need to see what 02 sensor is on the car and replace it. Might just do both while I'm there.

Sorry to hear of all of the problems. Just remember that a bad day racing is better than a good day working! Hope both cars are easy fixes.

Mine broke down on the way to Sebring back in 2014, just like you described, I was driving and then it shut off just like I had turned off the key. Was crank position sensor. The tow home was expen$ive, now I have the AAA "Platinum" or whichever one gives me a couple of 200 mile tows a year for free...

Yeah - we're premier AAA. The Q7 was covered - the trailer tow was not because it is a loaded trailer and considered unsafe by AAA. Never mind the fact the SAME vehicle towed both at the same time. Still waiting for a real explanation from AAA.

Thanks Tom. At least Q7 is still warranty. Crank position sensor ordered but I have to wait on the 02 to get the car off the trailer. Need a few people to help push it off and into the garage.

From your symptoms, crank position sensor would have been my first guess. "Like turning off the key". At least it is an easy fix.

That is a pretty hefty rig to pull with your Q7. 8,000lbs all in? Time for a diesel dually?

Hoping your next track day goes smoother.

This weekend we are heading to WSIR where there will probably be 250 Porsche sharing 2 tracks. Forecast is 95F on Sunday. Eeesh!

Yup - I was thinking that or fuel pump initially.

The car and trailer combined weigh just under 5,800 loaded - as it's a 20 ft Featherlite aluminum trailer. The Q7 usually tows it no problem as it's rated 7k and have the 3.0 TDI in it with 450+ ftlbs of torque. We are now waiting to here on the status of the "fix" for it and if that doesn't happen by November - then they'll buy it back. At that point we'll probably wind up with a truck, although this is my wifes car and daily driver. She's not really thrilled about getting a truck....

Pulled the sensor yesterday. Have no idea why it would have been chewed up on the side. A spare that came with the car had a similar mark but hadn't been cut through as severe. Sent a note to my mechanic. Ugh - after having the trans redone I really don't want to have to drop it again.

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Well - it appears that this indicates something pretty bad is going on with my crank and or flywheel. Spoke to my mechanic and Brad also chimed in - looks like a bad rear main bearing or warped crank or a small possibility is loose flywheel - is causing the starter ring to contact the sensor. Will be dropping it off to have the trans pulled. UGH.

That is a very odd failure. Keep us posted.

Does the car have a lightweight flywheel?

Yup - AASCO motorsports. Heading to the shop this Thursday.

I cranked the engine and peered in the hole of the CPS and you don't see anything come in view at cranking rpms.

Check the teeth on the rear of the flywheel that trigger the crank position sensor, we have see a couple with the teeth bent in such a manner that they hit the sensor. If that is the case, bang them back into position and you will be ready to go.

thanks for the tip and we'll look at everything but the thing is - it's hitting the side of the sensor - not the face. So something that is on the side of the sensor is moving.

So I got the word yesterday that it was in fact the flywheel. One of the three bolts that hold on the starter ring had backed out and finally fell out. It was at the bottom of the bell housing. So it was backing out and striking the CPS.

You can see in the picture of the AASCO lightweight flywheel there are only 3 bolts holding on the starter ring. Seems odd there is only three for this model as others models for 996/986/997/987 models appear to have six.

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So - I dodged a big bullet $$$ wise. Going to have the IMS replaced with the IMS solution from LN Engineering. Also - having them check the RMS and trans mounts to see if they need to be replaced while the flywheel and trans are out.

So the saga continues. Got a call yesterday that my engine is a newer version than I thought. I've always thought it was a 2004 but it is in fact a 2005. That means it has the same style IMS as a 997 - the kind that can't be replaced without cracking the engine. So no IMS solution. Still waiting to hear on the flywheel and whether they can add the additional 3 bolts.

Apparently the Boxsters get the 3 bolts and the 911's get the 6. Not sure why they went with the three bolt version - unless they were using the starter ring from the previous flywheel.

Boxster is back. We had a machine shop modify the flywheel to add three bolts for a total of six like the 911 flywheels. So now to get the car back on the track.

Great! Glad to hear it got fixed. My CPS crapped out at Chuckwalla Raceway, same exact symptom as you described in your first post.