Is there enough access to swap the FPR without the whole HP pump on this engine?

(200+ rpm was for the starter motor btw.  It won't be 900rpm until it catches).

25 minutes ago, Shearers said:

(I believe it is PWM i.e. a square wave, ON/OFF with different timings of those periods to control the rail pressure.)

FORScan can normally show the Live Fuel Pump Duty Cycle.

25 minutes ago, Shearers said:

So, the rail pressure looks like it  may be too high based on the pressure reading in Forscan, however you don't know if that is real or not (apart from @Tizer comment that injectors won't open if that s the case, so that may all match up).

So it's now a question of finding out if the high pressure is real or the sensor is faulty and then investigating the fuel pump control waveform to see if there is any evidence of actual control from there (I believe it is PWM i.e. a square wave, ON/OFF with different timings of those periods to control the rail pressure.)
I don't have many ideas left other than perhaps change the sensor to see if that changes anything, otherwise it's trying to measure the solenoid voltage (likely difficult to interpret) or needing an oscilloscope (again, difficult to interpret without a known good or being able to change the pressure to get the injectors to fire)
Only other thing would be to replace the rail pressure sensor with a variable resistor and starting with the resistance value that minimises the pump output and gradually increasing the output whilst observing in Forscan until the engine operates and seeing if any clues can be found.
I'd rather not get into guessing and changing parts without some evidence/justification, sorry I can't be more positive, excuse the rambling!

Thank you for rambling I appreciate your time on trying to help me out I’m going to swap the both sensors tomorrow and see if I get any results if I’m lost lol

Just now, Johnb1992 said:

Thank you for rambling I appreciate your time on trying to help me out I’m going to swap the both sensors tomorrow and see if I get any results if I’m lost lol

(If not I’m lost )

Just had another thought.

Normally when you switch the Engine off almost al of the Pressure in the Fuel Rail is dumped down the Return Line, so if you check the Pressure with just the Ignition on then it should be very little compared to when trying to start.

If it is still high then the Sensor on the Common Rail is faulty or is not being commanded to open or the Return Line is blocked.

1 hour ago, Tizer said:

Just had another thought.

Normally when you switch the Engine off almost al of the Pressure in the Fuel Rail is dumped down the Return Line, so if you check the Pressure with just the Ignition on then it should be very little compared to when trying to start.

If it is still high then the Sensor on the Common Rail is faulty or is not being commanded to open or the Return Line is blocked.

Thanks I will try this when I’m home  and see what it says I wouldn’t of thought return line would be blocked as I’ve pumped fuel through there 

Right just ran it with ignition on and yep it’s reading around 545 to 555 bar of pressure it’s bouncing up and down roughly between those numbers 

2 hours ago, Johnb1992 said:

Right just ran it with ignition on and yep it’s reading around 545 to 555 bar of pressure it’s bouncing up and down roughly between those numbers 

 

5 hours ago, Tizer said:

Just had another thought.

Normally when you switch the Engine off almost al of the Pressure in the Fuel Rail is dumped down the Return Line, so if you check the Pressure with just the Ignition on then it should be very little compared to when trying to start.

If it is still high then the Sensor on the Common Rail is faulty or is not being commanded to open or the Return Line is blocked.

Good news turned out to be the fuel rail sensor thank you all very much for your help I appreciate it 

Great to hear it is fixed after doing the diagnosis as far as was possible - you had information about the fuel rail pressure which gave as much certainty as could be obtained.
At my level, after collecting all the data, if I didn't have the equipment to go further, the suspected sensor would have to be replaced a it would be cheaper than buying expensive gear.

Thanks for coming back with the resolution (and to all contributors!)