Abstract: The pump described herein provides a potentially lower cost alternative to conventional high-pressure pumps by providing a head, a plunger, and a control valve assembly. The head defines a valve bore having a first diameter, a plunger bore having a second diameter, and an intermediate chamber having a third diameter. The plunger is configured to reciprocate within the plunger bore. The plunger, the plunger bore, and the intermediate chamber at least partially define a pumping chamber. The control valve assembly is coupled to the head and includes an actuator moveable in response to an input signal and a valve element coupled to the actuator. The valve element is received within the valve bore and moveable between an open and a closed position. The valve element includes a body having a fourth diameter and a valve head having a fifth diameter. The first diameter is no larger than the second diameter.