This vehicle came to us on the end of a rope.

Customer says vehicle driving normally
(maybe slightly down on power), when he felt a jolt, as if driving through a puddle.

He carried on driving for a couple of miles, with no other symptoms, warning lights etc.

He then stopped vehicle for a pick up (with engine still running) and it started to run rough and died.

It would then not restart.

When it came to us the battery was flat (wouldn't even attempt to turn).

Fault codes stored read with Delphi and G-Scan

P0685-00 Output Relay circuit 87 open circuit - Intermittent

P0266-00 Cylinder balance 2

P0272-00 Cylinder balance 4

Cleared and didn't return.


So far I have

Checked live data

Cranking gives in live data

Fuel pressure approx. 300bar fluctuating.
Engine speed 250rpm.
Cam/crank synch Yes.

Checked low pressure

4.4 bar into filter 3.5 bar out (so changed filter)

Low pressure flow approx. 1.5 litres when KOEO (pump runs for approx. 30secs).

Vehicle will start and attempt to idle for a couple of seconds if given a sniff.

Cranking gives

Relative compression shows even peaks.

Scoping FRP shows it rising from 500mV to 1000mV in 0.5 secs, but then oscillates from 1100mV to 900mV.

All four injectors are firing (amps clamp shows three peaks of 16amps then a short holding period of 8amps).

Leak back check on injectors

With 5mm clear hose

Injector 1 approx 175mm up hose
Injector 2 approx 50mm
Injector 3 approx 10mm
Injector 4 approx 150mm

With an 8mm clear hose on the rail return I have about 100mm of diesel.

So my question is!

Is this return on the rail excessive or am I on the wrong track?

Thank you