immediately after injection events when piston 60 and plunger 63 are hydraulically slowed and stopped residual high pressure in actuation fluid passage 48 can act against pressure relief valve 50 because pressure within spool cavity 47 is high spool valve member 40 is hydraulically balanced and can move toward its upward position under the action of biasing spring 44 pressure relief valve 50 can then lift off of seat 54 to open actuation fluid passage 48 to pressure relief passage 51 thus allowing pressure within actuation fluid passage 48 to be vented at the same time upward movement of pressure relief valve 50 and therefore pin 53 can aid in the movement of spool valve member 40 toward its upward position referring in addition to fig2 an orifice member 70 is movably positioned in injector body 11 orifice member 70 is preferably a variable area valve member that is positioned in needle control passage 39 and defines a portion of the same orifice member 70 includes a hydraulic surface 74 that is exposed to fluid pressure in an upstream portion 69 of needle control passage 39 orifice member 70 is movable within a spring chamber 76 which is also a portion of needle control passage 39 between an upward first position in which it closes a valve seat 73 defined by injector body 11 and a downward.