Fuel low pressure system too high P008B

[Muttly]

So,
I joined up the forum as it appears we've been sold a pup, 2019 Partner 1.5Blue.....Was told that it 'sometimes loses power going up hills...' So far replaced the complete wiper assy, the radio as the touch wasnt working, found there arent any front parking sensors fitted due no doubt to an earlier smash...Just invested in a DIAGBOX/LEXIA and its found the culprit, ie P008B. I've scoured the forums and cant find another PSA with the same fault. I've attached a scan report but have no idea what the 'normal' running figures should be?..If theres someone with a 100hp 1.5 and Lexia that could tell me the normal figures it may give a clue to whats causing this. Maybe someones had this before me?

Any advice welcomed..

[Mihael_M]

I have attached my report, it is not the same version of diagbox, so some items are different.

[Muttly]

Thanks very very much for a speedy reply.
From your report the fuel low press appears to be - Fuel pressure 5.031 bar. Mine is higher at - Fuel pressure 8.255 bar.
I have to guess that this is the root of the fault code. The low pressure pump is being requested at identical 27% so.... where to go??

[Muttly]

fuel px.pdf

(295.81 KiB) Downloaded 13 times

FYI engine off pressures...

[Muttly]

Started to invest the problem further and found what appears to be a regulator fitted into the space the fuel filter was fitted on earlier models. Its inline with the pump supply from the tank and feeds into the Pressure sensor (This is the fuel temp sensor, not pressure. Measures fuel delivery temp to HP pump) at the back of the engine, not the rail pressure sensor...
I've attached a picture and wondered if anyone could advise what this part does? It looks like a diaphragm regulator of some sort in the LP supply.. Before I tear out the HP pump. The script on google says the LP regulator is an integral part of the HP pump..

[Muttly]

[Mihael_M]

And on my car, there is that part next to the HP pump that I don't know what it does. But there is only the input and output of the fuel that goes on to the HP pump. No electricity, no connectors. Did you check if there is a sensor in the back next to the fuel filter?
In any case, it is better to check everything and possibly change (Sensor or this part) before touching the HP pump.

[Muttly]

I though it may be a one way check valve...to prevent fuel syphoning back from the hp pump but although it looks like a diaphragm construction, its blows freely in both directions. There is a directional arrow on it flowing to the pump. I called the main dealer today and emailed a picture but hes not gotten back to me today..I'll let u know if I find out what its supposed to do..
Dov

[PaulC5]

I did a google lens search (right click of mouse on the picture) on your picture and it came back with something very similar on ebay listed as a fuel tank valve with part number 9831640680 https://www.ebay.co.uk/itm/277130841856 It could well be a check valve as you suspect.