Truck Repair: cummins 350 big cam

Question
ford dump truck with a cummins 350 big cam engine. it runs great without a load on soon u load it loss of power. don't know if this will help but the fuel filter is only 1/4 of the way full. on a cold start it smokes until it warms up white smoke

Answer
If it's a davco filter that has a clear bowl on top with a filter inside those are supposed to be only filled up a inch above the clear. If it's a spin on filter that should be completely full of fuel. With that you could have a check valve bad causing it to leak back into the tanks. With the loss of power on it under load you could have a couple things a leaking injector or a bad o ring on your injector.