Fuel pump pre sure on 1985 Chevy blazer deisel

What is the question? Yes you need fuel pressure for the fuel to go to the injectors and pump diesel into the cylinders. You should have an electrical fuel pump. If your not sure it is working, turn all noise makers off in your vehicle before attempting to start it. Turn on the key but stop just before making the engine rotate. You should hear the fuel pump make some noise to pressurize the system. If you do not hear any noise, check the fuse to make sure it has not blown, thus preventing the pump from engaging. I hope this is the question you were asking. If you want to know the pressure needed in the system, that I don't know.