Hello, Mercedes gurus!

i’m kind of having problems with my MB R350 CDI.

Last winter my car would start right up when you turned the key, maybe 2-3 cranks and it started.

Approximately a month a go, I was driving down the road, when the car started to rattle and then turned off, I could turn it on again and drive for 100m but then it shut down and I couldn’t start it up anymore.
Dash was showing Range of 50km left, so I though that tank wasnt empty - but my dad came with his diesel can and filled 20L, and then after 10-15 second cranking car started up and ran ok after that.
I scanned the codes immediately when car turned off and it showed these codes:
11B600 - The minimum rail pressure was dropped below/ not reached
11B800 - The control deviation during rail pressure
regulation via the quantity control valve is too high
11B900 - The control deviation during rail pressure
regulation via the quantity control valve is too high
11BB00 - The rail pressure is too low during regulation via the quantity control valve
11BE00 - The control deviation during rail pressure
regulation via the pressure regulator valve is too high
11C000 - The rail pressure is too low during regulation via the pressure regulator valve

when I refilled the fuel, and started the car, i deleted the codes and they haven’t come back

BUT since this incident - my car has been running fine except one thing - when I start it for the first time in the day, it cranks exceptionally long - for 7-8 sec. After that you have started it once, other times in the day it starts immediately- 1-2 cranks.

what to do? How to diagnose the culprit?
could it be fuel pressure regulator?

I have the long cranking problem, but without the problems preceding it that you had. It came on suddenly without codes.

Did you ever figure out what was causing it?