That's what I meant - siphon the fuel up to the pump at installation, so you don't have any gas and don't have to rely on a vaccuum. As the pump draws fuel through the one way valve, the fuel continues to draw more fuel from below.
The first is that the fluid will draw a vacuum at the top of the pump. A vacuum on earth can only sustain 14psi - atmospheric pressure. For water, this constitutes a 33.9' column - after that you could draw a perfect vacuum at the top of the pipe and wouldn't the water to rise higher. Since diesel is less dense than water you might go a little higher, but probably not much.
The second problem is that as you create a low-pressure zone at the top of the pipe, the fluid will boil (cavitate). This gasified liquid will fill the space and drop your pressure. Oils like diesel should have a significantly higher boiling point (aka lower boiling pressure) than water, but it's still a limit.
