"The engine idles with the fuel pump relay removed"


Without pressure from the fuel pump, I have to assume that the injectors are not opening. Therefore, the fuel would be arriving through the intake. Is it possible that a leaking FD could provide a path to the return line which makes fuel available to the vacuum of the intake, allowing the engine to run without the pressurized fuel pump feed?

If so, adding pressure to the equation (assuming that the 3 bars necessary to open the injectors is maintained by the faulty FD) would mean fuel from two sources. A potential flooding situation. Is this logic sound? Is it enough to create a non starting situation?