Intermittent fuel supply 2008 CITROEN C5 1.6 hdi

[BKS]

I have looked for leaks although 1 injector is wet it is not running with diesel just sort of damp.

Advised by AA Fuel pump blocking. Just taken Fuel Feed Unit out expecting to find a pump, but there is no pump fitted just 2 pipes going into the diesel through the Unit. 3 pipes feed the unit.

Does anyone know how I can proceed to find out why the car cuts out especially after stopping at lights or won't run at speed all frustratingly intermittent, what am I missing?

[BKS]

i have no delivery from the High Pressure pump pressure outlet to the system that feeds the injectors.

i have attached a supply pipe fitted with a syringe to push diesel into the pump via low pressure inlet and turned the engine over, the pump just pushes the fuel out through the return outlet, nothing comes out of the pressure outlet.

is it the pressure relief valve or a failed pump, or something else?