One other thing to check before you go to the injection pump…it could be that the lines are clogged up.
So I would remove the lines between the injection pump and the injectors and then crank the engine and see if the injection pump is ejecting fuel out those ports. Now I warn you that the larger “nut” on top of the pump can rotate and mess up the pump so you MUST hold it in place with a wrench and then loosen the small nut that is on the injector lines.
I imagine that it really is the injection pump but this would be the last effort and if fuel did come out then you could clean or replace the lines.
If you have to repair the injection pump it is not something that can be done by the casual home mechanic. You will need to have it professionally repaired. There may be local diesel repair shops around or you can send it off to a shop like this
Oregon Fuel Injection provides diesel fuel pump testing and repairs as well as many rebuilt pumps on the shelf ready to ship.
oregonfuelinjection.com
You may be able to get a rebuilt one if you care to go that route.
There are (probably) shims between the engine and the pump face that sets the timing of the pump to the engine. Be sure to remove them and keep track of them since they must be installed with the pump (even a different pump).
I would also recommend replacing or repairing the injectors at the same time since they may be damaged or clogged.