Low fuel pressure codes

[malc4]

Hi all,

Citroen c4 1.6Hdi DV6C 9HR

I'm getting an intermittent low fuel pressure code appearing when accelerating (P0087).
After clearing it has come back with various additional codes:
P0272/P0263 (resetting of injectors outside tolerance)
P1199 (incoherence of reserve fuel pressure)
and most recently
P0093 (flow regulator blocked open?)

I'm hoping these codes indicate that the fuel pressure regulator is at fault and it's relatively easy to replace?

Is there any live data that could confirm?

Thanks

[RichardW]

Have you changed the fuel filter?

[malc4]

No, not yet. Filter less than a year old tho.
I've done an actuation test on the fuel pressure regulator- seems ok.
Also captured the fuel pressure data as it threw the P0087 code

Revs 2500 and increasing:
Regulator open cycle ratio increasing from around 25% to 43% -normal?
Measured fuel pressure starting to fall behind instructed with until at about 3000 revs the pressures are 850 vs 1400bar
but then suddenly they flip for a while - measured rises/maxes out? at 1800bar with instructed <1000br before coming together again at lower revs (after fault code triggered).
I'm naively thinking this is now looking like a bad pressure sensor, but i guess other things could cause this odd data?

Time to get my hands dirty;)
I'm going to fill the new filter with Carlube injector cleaner like O'Reilly does;) May also clean the fuel sensor and resolve contribution balance of injectors. That's why i want to do a leak off test before i do anything else

[malc4]

I've dived in with replacing the fuel filter and priming with injector cleaner. Ran it for a few min and will let it rest for a while.

I noticed the fuel draining from old filter had quite a few yellow/brown flakes. Any ideas what this could be? Maybe I'm onto something and my initial guess of bad fuel is the cause?

[malc4]

Have dismantled the old filter and there's a brown sludge covering everything- diesel bug?