I would change the fuel filter as first port of call on any TDCI faults, have seen people replace injectors,fuel pumps and all sorts when all was needed was a fuel filter.

Be aware you really need some kind of hand primer to fill the filter & prime the low pressure side of the fuel system, as these vehicle do not have a lift pump in the tank.

You really need to make sure the low pressure side is primed BEFORE attempting to start it, as once air is introduced into the rest of the system it can be a bugger to sort...

Have you had fault codes checked?