Fluid Dynamics (or how does this diesel thing work?)

[Mad Maxine]

In my ongoing quest to figure out my air intrusion problem, I just want to make sure I have it in my head straight about what is going on in my fuel system that's causing me the problems.

The air is causing the fuel system to lose it's prime by allowing the fuel to drain back to the tank, is that correct?
And then the hard-start is caused by the fuel pump having to pump diesel all the way back up to the IP?

Thanks!

 

[icanfixall]

That can be true but you need to find where the leak is happening. If its from the injection pump then the filter will be full but the pump is dry. The engine fires up but dies in a few seconds. Then the cranking to refill the mt injection pump. Otherwise you are correct that the fule runs hack to the tank but only if the mechanical lift pump has failed in that the check valve is allowing the fuel to run back.