The fuel check valve is built into our fuel pumps. When it goes bad, it leaks back fuel pressure into the tank and will create a hard(slower) start due to no pressure(fuel) at the injectors. When check valves go bad, you need to change out fuel pump, or install an inline check valve between the fuel pump and filter/regulator(Needswings sells these). As far as doing the leak down pressure test; search for the SRT6 service manual PDF in our Forum here. It will tell you exactly what to do (In English). Perhaps you need a better translator??
Good Luck.