Okay so to reiterate. Put a one nipple banjo bolt in place of the two nipple banjo bolt on the return side. Place a section of hose one end on the one nipple banjo bolt and the other inside a jar full of diesel. Gravity feed the pump through the return line? NOPE to this! Both lines go in the jar and you are looking to have the IP pump pull the fuel in like normal and then spit it back out from the Out side into the jar or jug. If fuel is sucked in then the lift section checks out. If fuel does not flow from the jar into the pump then something is wrong with the lift part? Bingo, Give that man a dollar! If the lift part checks out. Remove the one nipple banjo bolt and place a fuel hose directly inside the hole on top. NOPE again. He said to replace the IN bolt you subsituted for the Out. Set it up as it was, with the two nipple one and send the fuel back to the tank. What he wants you to do then is take off the fuel solenoid and remove the spring and the check valve part. This will make it so fuel will always flow through the pump, esentially manually over riding the electric on or off capability of the solenoid itself. This will eliminate the possibility that the valve itself is a problem in the system. Remove the plunger from the cutoff solenoid and crank the engine. If fuel comes out of the injector lines the cutoff plunger is the issue. Correct? Yes!!!!