01 f450 250k miles. started getting bad mileage, loss power, ect. decided time for upgrades. new injector o-rings, up pipes,rebuilt turbo, glow plugs, exhaust. put it all together. on test run blew all the oil out threw o-ring on turbo slipped out when installed.has not started since. replaced ipr, icp, oil pump. 0 oil pressure on startup.65% ipr duty cycle. pulled injectors again to check for leaks all looked good. low pressure is good, resivoure is full, sump full. i'm really at a loss any one have any ideas.