The present invention relates generally to variable discharge pumps, and specifically pumps used in fuel injection systems. Typically, such pumps include a dedicated spill control valve for each pumping plunger, that also doubles as an avenue for refilling the pumping chambers. This double duty results in compromise in the design of the spill control valve to operate effectively in both spill and fill modes. The present invention addresses these issues by utilizing a shuttle valve member to allow the spill function and the fill function to be addressed in separate passageways while also allowing a pair of plungers to share a common spill control valve. The present invention find particular application in pumps used to supply high pressure fluid to common rails for fuel injection systems.