E70 35D Stall while driving crank no start
 

My E70 11/2009 35d is giving me issues. The engine cut out while driving up my driveway yesterday and would not restart. It turns over OK and has not made any noises that I would expect if the timing chain had broken.

I have a Foxwell nt510 and checked for codes and got the following, unfortunately I haven't scanned this car before (relatively new purchase) so not sure which of these may be preexisting:
4252/present/glow plug cyl 5.
4262/present/ glow plug cyl 6.
3EC0/not present/DDE camshaft sensor signal
3EC1/not present/DDE camshaft sensor signal
41f2/present/DDE Electric fan activator

53fc/present/VTG Supply control unit terminal 30
54c6/present/VTG oil wear

D36A/not present/ no message (VTG, OXBC) receiver DSG transmitter VTG
5F3A/present/DSG Transfer case malfunction

I suspected a fuel supply issue so checked the fuses for the fuel system, checked the fuel system relay.
I listened for the LPFP running with ignition on but couldn't hear it, so I ran the pump using the Foxwell and confirmed I could hear the LPFP running.

Still following up on the fuel supply route I thought I would check the fuel rail pressure and found it was only showing 80bar. The unit is reading 8.7bar rising gradually to 80bar during cranking, required pressure 300-320 bar indicated. When I stop cranking it rapidly drops back to 8bar.

Thoughts/comments/suggestions?

Bad crankshaft sensor can cause no start. Looks like you have a code for it, I would take a look at that.

Not sure how that might also cause a low rail pressure?

I seem to recall the DME will not activate the fuel pump if it sees no crank signal...

As a "while you are in there" check on changing/verifying the crank sensor
pull the metering unit off of the CP3 pump and look for metal flakes. Had the same no start condition and the CP3 had eaten itself due to water contamination.

Maybe try clearing the codes and seeing if it will start?
Or seeing what codes reappear when you try and start it.

The only codes there that look like they might be related to your no start condition are the below, but it says they're both not present.

3EC0/not present/DDE camshaft sensor signal
3EC1/not present/DDE camshaft sensor signal

CP3 = High pressure pump right?

by the metering unit do you refer to the 'control flow regulating valve' in some documents?

Any bleeding process if metering removed/replaced? Run low pressure side using scanner?

Thanks for the advice.

Phil

Agree that these are the only significant codes, and they are sticky. but I'm getting advice from others that camshaft position sensor should not cause a running engine to stall.

Do you have a different experience?

Phil

Correct. The high pressure fuel pump. No special steps since it is a visual check to see if there are metal flakes present on the regulating valve. At most some paper towels to catch the fuel draining out of the pump. On restart the low pressure pump will fill to the HPFP.

Gave up on taking out the regulating valve. Just couldn't get to the third (lower) bolt without taking the manifold off. Tried all sorts of gymnastics with double quarter drive universals etc but no way I could get the torx engaged. So I went under the car and put a manual pressure guage on the downstream end of filter (6-7 bar with pump run on 120l/hr using Foxtel) Then pulled filter. Upended the filter into a glass jar. perfectly clean diesel, no water, no sediment and no metal flakes. I'm hoping that means my HPFP is ok.
Not exactly sure what to do next. I hate to swap parts without a solid diagnosis.

Rail pressure regulating valve off back of rail?
Control flow regulating valve off pump.

Seems like I have to remove manifold for either which also means disturbing a million other connections.

I'm concerned that i'm missing something else which might be leading to the DME downregulating the fuel pressure.