cytroen cynergie 2l hdi?

i have a cytroen synergie 2l hdi the engine cut out after awhile and hard starting it ran agin , but got worsre and will hardly start if it doe,s it runs for about 10 seconds very lumpy,black smoke ,likes its burning to much diesel. when u turn on ignition there is gurgling in the fuel tank...any ideas...been told could be injector, or timing slipped.