Bernd
The mechanically driven Fuel Pump mounted on the engine is "Low Pressure"? This is counter-intuitive to this mechanic, the HP pump must be by definition "last in line". Driven by a steel shaft which derives its power from the engine gearbox suggests High Pressure. Also, it is my understanding that the engines will run fine on "suction" alone. Back to school for me. (Read: suction/gravity). My impression also is that the high pressure pump is "geared" or lobed; impellors ("vanes") are more susceptible to cavitation.
Airfoil