What should the fuel system pressure be before cranking the engine? I'm asking as when I had it connected to diagnostics earlier it was idling at approx 5000 psi and then when the engine was turned off it decreased somewhat, fluctuating between 35 & 67 psi?

The fuel pressure regulator was replaced a couple of days ago which has helped starting but the engine stalled again today!!!!!! This is getting very frustrating now. Just praying it's not the fuel pump which according to the diesel specialist the other day was working fine.

 

What about an Injector leak off test, that's your other loss of pressure area.

 

Have a look here for a graph of fuel pressure. The pressure does decay as soon as the engine is turned off.

Fuel Pressure Sensor – Common Rail Diesel automotive waveform captured using a PicoScope automotive oscilloscope

Regards
Richard

 

Oh here something else to take note of. Pity we couldn't sit a sat-nav/phone type screen on our dash top and watch this graph happening then any variation would tell us something is on way out.
However how much does the pressure need to be out of requirement to cause shutdown or limp mode tfb.

 

So if there is a pressure leak at the pump is this an indicator that the MPROP is faulty or also fuel pump internal fault? I will next check the injector leak back again as now that the MPROP has been changed and the system is running at a more efficient pressure it may have caused any small fault in the injectors to be exaggerated. It threw a p1130 code again yesterday when it cut out on the wife. Obviously there are a few issues with this vehicle.

 

Just finally got round to fixing the car today. Swapped out the injectors (with many thanks to scotsman4th lending me the removal tool) after having the fuel pressure regulator changed and she is running like new again. Once the regulator was changed it ran ok for a day or two but then set off a chain reaction, exposing faults with the injectors which were in tolerance before the new part was installed.

Anyway I had a small drive earlier and am now pleased to say it feels a lot smoother and the fuel economy has drastically changed. I am now getting 30-33mpg instead of 15-18mpg.
Still not 100% happy with the starting of the engine but I believe that is most likely due to the excessive cranking over the last few months taking its toll on the battery. My next step is to renew the battery and a few suspension parts. Many thanks for all of your help on the various posts I have made regarding this. It could have been very costly without your knowledge and guidance.

Regards Dan