how can i fix my fuel problem. 1993 ford transit 2.5 diesel?

I woz driving home then my van started to lose power and the revs died off like it ran out of diesel.(but i had half tank)I managed to tow the van home and tride to start it again. the engine turned over but did not fire. i opened the bonet and deicided to open one of the injectors to see if any fuel came out when i cranked the engine. after about 30 secounds of cranking the engine over the fuel came out so then i quickly tightened the injector up as it fired. then the van started but run realy poor then cut out after a minute. i repeated this 3 times and had the same result. I deicided to replace the fuel filter because i thort it would be bloked with crap from the tank. I filled the fuel filter up with diesel before replacing it.and bleeded the fuel again through the injector and it started up and ran till it warmed up then cut out again and did not start back up. it will onley start when i bleed the fuel through the injector but runs for a few secounds then dies. is my fuel pump knackerd?i would realy apprecate your help thanks...