A fuel pump assembly for an internal combustion engine; the pump 2 comprising: a housing 4 including a plunger bore 8; a plunger 10 reciprocating within the bore to perform a pumping cycle comprising pumping and return strokes, to pressurise pump chamber 18. A drive means drives the plunger through its pumping stroke; and a spring assembly 43 applies a force to return the plunger and maintain contact between the plunger and the drive means during the return stroke. Wherein the spring assembly comprises: a return spring 14 to provide return force over the entire return stroke; and an additional spring 42 to contribute to the return force during an initial portion of the return stroke as the plunger 10 moves from its TDC position towards its BDC position, and to cease contributing to the return force before the plunger reaches the BDC position. A method of manufacture is also disclosed.
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