Waste gate actuator

OK the TD4 has been running perfectly with her new set of injectors. That is until this week, no boost. The rod that is attached to the variable vein mechanism moves freely, well sprung resistance. I put constant vac hose from boost solonoid to diaphram but it does nort move. So either:

Vacuum is not greater enought to pull diaphram or diaphram is not holding vacuum?

Can you buy the diaphram actuator seperately just hope its not like audi and you have to buy complete turbo which seems crazy when the part must be a few quid?

Anyone else had this problem?

OK been messing around with this solonoid (diaphram) if I take of the vacuum pipe from the diaphram there is constant vacuum. Should there only be vacuum when boost solanoid activates? Any help would be appreciated

Meant to say attached hose to diaphram created vacuum with large syringe. The wastegate rod moved but did not hold in place it returned to it orginal position, as if there was a leek in the diaphram?

Sorry no advice just dropping in to keep an eye on responses so I can check mine. Hope you get it sorted soon.

Sure its not electrical? Fuel rail sensor fault would cause this too, they are prone to water ingress/corrosion i believe, worth checking the connector, its behind EGR valve. Reason i know is mine was loose and became disconnected causing your symptoms

Have you checked the vac hoses for leaks, check across the top of the engine?
With engine idling what should happen is, when you bypass the solenoid putting the vac pipe from the vac chamber direct to the capsule on the turbo the rod should move across and stay there until you remove the pipe again. If it isn't you could have a hole/leak in the vacuum pipe or faulty solenoid.