[mike1967]

its also possible a injector is breaking down they are piezo type and are prone to failure or inner seal and it bleeds off rail pressure on cranking, live data run and watch what rail pressure you have it should be 200-250bar ish on cranking, if very low then pressure reg on fuel pump, injector issue do bleed off test, also live data will show all the injectors duty times with mg's ie milligrams per second of fuel on each injector, ie looking for a that stand out ie is 3 show minus 0.2 and one says minus 0.20 then that would be the cylinder that needs looking at,, before throwing injector away worth buying some seafoam and add it neat to fuel filter then take for a good hard run ie 3k and above see if will clear the dirt if down to that,
glow plug relays fail a lot as do the glow plugs, heads up only ever try and remove the glow plugs with engine nice and hot more likely to snap off doing them cold, also the relay is same as Peugeot Citroen 1.6hdi same years ie 2006-2010 and are cheaper to buy

 

[mike1967]

the 1.6hdi 2009 diesel engine does not have a in tank 12 volt fuel pump, it does not have electronic pump so switching the ignition on and off will not make any difference, the fuel is reliant on the fuel pipes being sealed and the high pressure pump has its own part f the pump that draws the fuel in to it ,, the later bmw n47 diesels after 2010 march do have in tank first stage fuel pumps, if you look on top of engine under the little square plastic panel there is a oblong plastic bleed ball that has a non return valve in it to prime the fuel, if before you try to start car you pump this ball maybe 20-30 times fast then start car and it starts right away chance are you have a air leak in fuel line somewhere, or maybe fuel filter has failed common on cheap filters