1995 Internataional Dt466 injector pump, Please help!!
 

So me and a friend bought a 95 schoolbus with a dt466 running and driving for 850$, so we drove it around a bit and it ran like a top. Then we go to drive it out to the farm and it was running fine and then it was almost like the rack stuck when i let off the accelerator. so i pulled the fuel shut off and coasted to the side of the road, When i went to start it again it wouldnt fire. we pulled it the rest of the way to the farm, i took the lines off of the top of the injector pump and we turned it over, no fuel came out. so i checked if there was fuel at the lift pump at the banjo bolt on the bottom of the injector pump and there is. Ohh and by the way i im not sure if it is the bosch P pump or the MW. i took the two nuts off on one of the barrels on top of the pump and pulled the barrel out, Is that OK? is that gunna mess stuff up? i looked inside and turned the motor over and the plunger was moving up and down and there was fuel going in there too. Please help i dont know what to do and need this thing running