Hello all

Have the above vehicle at the moment that has an intermittent cutting out (approx once a month)

Managed to get to cut out on gentle pulling away and would not restart

Diagnostic trouble code stored before and after cutting out was:

4B90
Rail-pressure monitoring on engine start
Rail pressure too low during engine starting

On cranking looking at live data fuel rail pressure would max peek at 140bar and quickly dropping off to approx 10bar

When cranking and not starting I managed to do a injector leak off test with no spill return

But unfortunately before i had chance to do a low pressure feed test the vehicle started with 380 bar pressure within a second or two of cranking

Low pressure when running at Idle and when reved was 73psi with 2.5 LPM Flow rate.

Have been unable to get the vehicle to fault again.

Question is are there any known faults so i can concentrate my investigations for this and not have to wait another month

Below is the scope capture of Fuel pump current draw, fuel pressure regulator and fuel pressure sensor With engine running at idle




Thanks in Advance

Terry

Where in he circuit did you scope your pump ?

I traced fault on mine to a fuel pump relay fault, locate behind glove box. ( AD relay layout data is incorrect )

Cheers Aidan