A proportional control valve for a fuel pump, comprising: an inlet check valve cooperating with a valve seat, wherein the inlet check valve has a closed position against said seat during a pumping phase of said pump and a variable open position to permit hydraulic flow through the seat in a downstream direction to a low pressure passage in the pump during a charging phase of the pump; a main spring that acts on a downstream side of said inlet check valve to provide a biasing force on the inlet check valve toward said seat; a hydraulic plenum that acts on the upstream side of said inlet check valve, in opposition to said main spring, whereby when a force on the inlet check valve due to pressure in the hydraulic plenum exceeds the biasing force of the main spring on the inlet check valve during the charging phase, the inlet check valve opens, permitting hydraulic flow to said low pressure passage; a sleeve with upstream and downstream ends, defining a piston bore and an inlet port passing transversely through the piston sleeve into the piston bore; a feed plenum for supplying fuel at a pressure higher than the pressure in said low pressure passage, to said inlet port; a metering piston having metering and non-metering ends, slideable within the metering piston bore along a first direction to a first position that covers said inlet port and seals a flow path to said hydraulic plenum and along a second opposite direction to a variable second position that respectively variably opens said flow path to said hydraulic plenum and said inlet port, whereby the opening of the inlet port establishes a flow path from said inlet port to said hydraulic plenum such that the hydraulic plenum applies hydraulic feed pressure to the upstream side of the inlet check valve; an actuator connected to the metering piston for selectively sliding the metering piston between said first and second positions; a fluid chamber at the non-metering end of the metering piston; a leakage path along the piston bore of the sleeve, from the inlet port to said fluid chamber; a vent valve between the hydraulic plenum and the fluid chamber, connected to the actuator, for exposing the fluid chamber to the pressure in the hydraulic plenum before the actuator moves the metering piston from the first to a second position. an inlet check valve cooperating with a valve seat, wherein the inlet check valve has a closed position against said seat during a pumping phase of said pump and a variable open position to permit hydraulic flow through the seat in a downstream direction to a low pressure passage in the pump during a charging phase of the pump; a main spring that acts on a downstream side of said inlet check valve to provide a biasing force on the inlet check valve toward said seat; a hydraulic plenum that acts on the upstream side of said inlet check valve, in opposition to said main spring, whereby when a force on the inlet check valve due to pressure in the hydraulic plenum exceeds the biasing force of the main spring on the inlet check valve during the charging phase, the inlet check valve opens, permitting hydraulic flow to said low pressure passage; a sleeve with upstream and downstream ends, defining a piston bore and an inlet port passing transversely through the piston sleeve into the piston bore; a feed plenum for supplying fuel at a pressure higher than the pressure in said low pressure passage, to said inlet port; a metering piston having metering and non-metering ends, slideable within the metering piston bore along a first direction to a first position that covers said inlet port and seals a flow path to said hydraulic plenum and along a second opposite direction to a variable second position that respectively variably opens said flow path to said hydraulic plenum and said inlet port, whereby the opening of the inlet port establishes a flow path from said inlet port to said hydraulic plenum such that the hydraulic plenum applies hydraulic feed pressure to the upstream side of the inlet check valve; an actuator connected to the metering piston for selectively sliding the metering piston between said first and second positions; a fluid chamber at the non-metering end of the metering piston; a leakage path along the piston bore of the sleeve, from the inlet port to said fluid chamber; a vent valve between the hydraulic plenum and the fluid chamber, connected to the actuator, for exposing the fluid chamber to the pressure in the hydraulic plenum before the actuator moves the metering piston from the first to a second position.