BMW 320d N47 Another one that cranks but doesn't start…

BMW 320d N47 Another one that cranks but doesn't start…

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Colsworth

Original Poster:

2 posts

12 months

Friday 24th November 2023
quotequote all
Hi.

I am trying to fix my sons car, a 2012 BMW 320d N47 Diesel engine. Have reasonable experience of engines but pretty old school...

Story and symptoms are:
Stopped when driving, just slowed down no power and too a halt.
Hasn't started since except when on go-go juice...
Engine cranks but doesn't start.
Engine runs with a small spray of easy start for as long as easy start keeps it going.
AUTEL tool says 300bar fuel pressure and 300 bar setpoint near as dammit. (I thought common rail pressure was supposed to be >1,500 bar but setpoint and actual presssure the same.)
Fault code of low rail pressure sometimes coming up but that's all.
Cams are turning when looking in the oil cover.. obviously would have to be for engine to start.
No correlation between cam and crank sensor listed by scanner tool.
All injectors have pulses on mulitmeter meter with Hz reading.

I am flummoxed.. seems like fuel issue but pressure seems to be good.. if its timing issue I thought it would pull up a correlation code as VW does...

PLEASE HELP.. Pulling my hair out... :-(


Huskyman

655 posts

134 months

Friday 24th November 2023
quotequote all
Hi,
Sorry to hear you have problems. What fault codes do you have and what scan tool did you use? 300bar sounds low to me. If the car will run on start fluid then chances are it’s a fuel delivery fault.

rottenegg

805 posts

70 months

Friday 24th November 2023
quotequote all
If there's no crank - cam correlation, that is one reason why it won't fire up. Timing drifted out of spec perhaps? That is also a fairly common crank no start situation with modern DI petrol engines as well.

How did the engine cadence sound during cranking? You can normally hear it when compression is down a bit from the timing being out of whack.

If you're seeing 300 bar pressure whilst cranking I think we can outrule the in-tank pump.

Colsworth

Original Poster:

2 posts

12 months

Saturday 25th November 2023
quotequote all
Hey thanks for reply guys.

Sorry should have said NO Crank and cam correlation error on computer.

The only error that comes up after reset is sometimes low fuel rail pressure plausibility????

Away to get back at it this afternoon.

Cheers.

Huskyman

655 posts

134 months

Saturday 25th November 2023
quotequote all
Colsworth said:
Hey thanks for reply guys.

Sorry should have said NO Crank and cam correlation error on computer.

The only error that comes up after reset is sometimes low fuel rail pressure plausibility????

Away to get back at it this afternoon.

Cheers.
Can you get live view on your diagnostic to see if the rail pressure changes or remains static when cranking?

I-am-the-reverend

921 posts

42 months

Saturday 25th November 2023
quotequote all
High pressure fuel pump failure is common on these as well as VAG rubbish. The pump starts to break up, steel swarf goes into the tank and back around again to destroy the injectors.

This is the later 'improved' CP4 pump that replaced the previous version around 2007.

Look in the fuel tank with the pump removed and chances are you'll see glitter in the diesel.