Check the fuel solenoid.
Check the individual resistance of each glow plug AND the total resistance of all four. Make sure the glow plug relay is working.
Take the glow plugs out and check the cranking compression.
If the glows are all in spec, the glow relay is activating, the fuel solenoid is operating, the fuel system has been primed, and there is adequate cranking compression, then it will either run or you have a problem in the injector pump or governor assembly.
I believe that motor uses a mechanical injector pump that you set the ijctor timing weith shims. Remove #1 injector and see how closely the spray timing corresponds to the injector timing mark on the crank pulley.
Hope these vague guidelines are helpful.