HELP!!! 2002 Picasso 2.0l HDI, Low Fuel Pressure fault

[avamotor]

Hello FCF,

Yesterday was supposed to be a steady day, getting ready to weld the passenger side inner sill on the 307 when the phone rang and i was greeted with:-

"Picasso's broken down, cranking over but wont start up so i'm waiting for AA". Waited not too long before got an update of "suspecting lift pump in tank but will let you know". Then informed that some "Carb Spray" was sprayed into air pipe and car fired up. It is now suspected that due to low fuel pressure its probably not the lift pump but instead either the fuel rail sensor, or the fuel pump regulator sticking or the fuel pump itself.

The email from the AA later received states "engine cranking okay but not firing, checked live data found fuel pressure low only 11-12 mpa on crank, in tank pump running OK, fired on carb cleaner runs, suspect fuel pressure regulator on pump sticking". With the engine running (after carb cleaner asthma aid) I plugged in Lexia and took photos of the relevant live date whilst running as i knew the instance the engine was switched off it would be game over.

How is it possible to "bench test" a fuel pump regulator sensor, i tested the lift pump this morning by putting feed pipe straight into fuel filter housing switching on ignition and pipe supplied diesel, confirming in tank pump confirmed working okay. I guess the injectors are okay as with the engine running on Carb cleaner boost, it runs as it did so its just the initial powering up and pressurizing.

I have cleaned out the fuel filter housing and found only very minute metal fragments, only half a dozen or so about as big as silt so nothing considerable and put in new filter. I have also ordered a known good fuel rail sensor and am trying to find/track down a fuel pump regulator to fit a Bosch (515),
CR/CP1S3/R65/10-16S,
0445 010 046,
4C Made in Czech Republic.

Questions!!

Are the pumps compatible across the 2.0l hdi range of similar years etc will engine code RHY and RHZ be compatible or as long as the 0445 010 046 number is on the sticker will it fit mine?

Do it sound like a sticking fuel pump regulator sensor or the fuel rail sensor could cause this as i cant find an awful lot on the internet about testing/cleaning these?

Would appreciate any advice apart from torch it, anyone else suffered with similar symptoms??