is coupled to the actuator armature 110 of an electronically activated solenoid 112 in fig1 the solenoid is shown activated displacing the poppet valve a short distance to its closure position preventing hydraulic fluid from passing to the port 100 key to the operation of the fuel injector system 10 is a hydraulic pulse pump 114 which has a pump cylinder 116 with a floating piston 118 that divides the pump cylinder into a hydraulic chamber 120 and a gas chamber 122 the free floating slide piston 118 is biassed by a compression spring 124 in the hydraulic chamber 120 to displace the slide piston 118 toward the communicating passage 16 with the combustion chamber 18 the hydraulic chamber 120 communicates directly with the hydraulic fluid conduit 40 that is filled with hydraulic fluid from the fluid supply 36 through the check valve 38 when the pressure of the fluid supply exceeds the pressure in the combustion chamber 18 shifting the slide piston 118 is shifted toward the passage 16 in operation as the pressure in the combustion chamber 18 builds during compression and initial ignition the slide piston 122 is displaced toward the fluid conduit 40 transferring the pressure of the combustion chamber 18 to the entrained fluid in the conduit.