2002 Chec Cruze M13A cuts out when hot

When the engine temperature gets to the point where the fans come on the engine will occasionally splutter and die
when left idling for a while. Usually around 95 degrees Celsius. At first the Cam sensor was giving a strange pattern when
it died so I thought it was heat related and replaced that - but it still does it, almost like clockwork. I've recorded some images
from the Snap-On Solus that graphs all the live data while it's running. Near the end of the pattern you can see where it starts to die.
Fuel pressure stays constant at 45 psi when it's idling even when it dies. I've smoke tested the intake and there are no leaks.
Just before it dies there is a slight change in tone of the engine, then it starts to make a sucking noise like someone has put their
hand over the intake. Then the engine starts to stumble badly and dies. This all usually happens after it has reached operating
temperature and the fans have kicked in a few times. 95 degrees C, which would be 203 F.
I scoped the ignition coils and they both keep sparking, and the plugs are clean. I'll scope the injectors next.

Everything looks good electrically, both coils are sparking, two new coils were tried to make sure the spark we are seeing is actually getting to the plugs - it still cuts out. Looks like a mechanical issue. I did a compression test but can't do it at the temperature the vehicle cuts out at because within the 5 minutes it takes to pull the plugs out it's back to the temperature where it could run well anyway.
Time for the mechanics to pull the rocker cover off I think.

Okay here is a theory, if the issue arises when the fans cut in it makes me think you could have a power or ground issue. Fans take a huge electrical load so could show a high resistance in a power or ground.

Thanks, but sometimes the fans kick in and out a few times before it happens, and it happens even
when the fans aren't running, but at the temperature they often work at.
I'm actually wondering if it is something like a very thin valve clearance that opens up a cylinder or two
when it gets hot enough.

I'm starting to think it may be something like tight valves that cause loss of compression when it heats up.

This is what the coil pulses do when it dies. I'm busy scoping cam and crank sensors again.

I didn't scope the crank sensor at a high enough frequency before - it starts to get gaps just
before the engine dies.

That's a great capture.

Dwell time on channel #1 goes way too long. FWIW, in addition to the cam/crank, I've seen this caused by failing ignition coils. They'll leak secondary voltage into the signal circuit and cause the other coil driver to malfunction.

EDIT: Oops, didn't wait long enough for the cam/crank capture!

This is cranking, no start, after it has died. The crank sensor pulses are scarce.

After it stalls and When it cranks no start, it makes me think ECM is failing when it gets hot. Can you disconnect the crank sensor from the harness and scope capture the crank signal then? My idea would be to eliminate the ECM (possibly shorting) from causing the crank signal problem. Just a thought.

John Curtis wrote: After it stalls and When it cranks no start, it makes me think ECM is failing when it gets hot. Can you disconnect the crank sensor from the harness and scope capture the crank signal then? My idea would be to eliminate the ECM (possibly shorting) from causing the crank signal problem. Just a thought.

Thanks, I have a new crank sensor on its way. I don't think the heat is reaching the ECM however the crank sensor is mounted under the alternator [miserable place] and the fault hangs around for about a minute after the vehicle is shut down so doesn't give much time for testing. The oscilloscope is a wonderful tool though for 'later observation'