Just a thought... when I was timing mine I had a difficult time getting the injection pump gear to stay put as is it kind of spring loaded right where you need it to stay and it will go either way if it's not held in place.
This was a trick I learned... Don't tighten the tensioner pulley until everything is in the proper mark. If you keep it loose you can put a socket on the nut that tightens the gear to the injection pump and it will turn/slip under the belt but the belt itself won't move. That way you can align everything and then turn it until it is dead on in the proper slot in the belt. I hope that makes sense. Makes it easier to do it by yourself.
Something else to consider is to remove the glow plugs and loosen the fuel lines. Turn over the motor for like 30 seconds to work some oil into the head and to make sure fuel is flowing from the fuel lines. It will spin real fast without the compression. Then put everything back together. There could just be some air bubbles and it's not all cleared out yet. Prime your fuel filter first too.
Good luck! Let us know your results.