We are sorry to hear that you had a bad experience here at Dan's. Let us take the time to explain our actions for you.
Your 2004 F-350 was towed to us from another body shop having the complaint of running bad. It only ran once at our shop for about 15-20 seconds. After connectiong our top of the line SNAP-ON Solus Ultra diagnostic scan tool to the truck, we found that it wasn't building enough fuel pressure to work the injectors. This vehicle needs 500psi to start and it was only making about 50-75psi. The fuel system in the truck uses engine oil pressure from the mechanical oil pump that feeds oil throughout the motor.
This engine takes the engine oil pressure, about 70psi, and feeds the high pressure oil pump that increases the oil pressure at the injectors from 500psi to 4000psi. The pressure is controled by the Injection Pressure Regulator (IPR) valve. The IPR valve is controlled by the Power Control Module (PCM). An Injection Control Pressure (ICP) sensor is mounted on the high pressure pump and sends a signal to the PCM to control the high oil pressure to the fuel system.
Our next step was to follow the instructions in order to check mechanical oil pressure. We removed the oil filter and pushed down the valve at the bottom of the filter housing. At this point, you turn the engine over with the key and watch for engine oil to start filling the filter housing. We found no oil came into the housing at all. Next we removed the oil pressure sending unit to the gauge and turned the engine over with the key and no oil came out of the port.
Following the tips in our information system, Mitchell, we added four quarts of oil to the engine and repeated the test for engine oil pressure. We found that there was still no pressure at the filter housing or the sending unit port. The reason for adding more oil is to raise the level in the engine to see if the oil pump pick up tube is cracked or broken off.
We concluded that the engine oil pump needs to be replaced because this engine builds no engine oil pressure. Once discussing this repair with the insurance company, we were told to stop all diagnostic and repairs and that the vehicle would be towed out of our shop.
I hope this helps clears up some misunderstandings you may have about the actions we took to diagnose your vehicle. Take care!