I am out of ideas, and think I have the problem figured out, but could use some backup. 2006 Mercury 25hp 4 stroke. Good battery. Turn key, no beep and no HP fuel pump running. Motor will turn over but won't start. No fuel pressure at fuel rail. Mechanical fuel pump works fine, HP fuel pump works with direct wire connections. New fuel pressure regulator. Good spark. Motor will start and run when fuel is introduced via the intake manifold. I have troubleshot everything I can think of and have replaced the cheap stuff- and I'm down to a bad ECU as my next guess. Any input or ideas would be greatly appreciated!