Abstract: An open-vane regenerative impeller for a fuel pump. The impeller has a ring-like body portion from which a plurality of open-vane impeller vanes extend radially out and a plurality of fan blades extend radially in. The impeller is disposed in a closed cavity between two pump bodies with the vanes in an annular pumping chamber and the fan blades in a cylindrical vapor collection chamber radially inboard of the pumping chamber. The fan blades operate to blow vapor out of the vapor collection chamber through a vapor discharge slot in one of the pump bodies when rotation of the impeller commences thereby to enhance the initial vacuum at the inlet port to the pumping chamber.