A fuel pump system for pumping fuel to an engine in a vehicle includes a pump motor having a carbon-based commutator and brushes in a position exposed to fuel, resulting in a tendency to form a film between the commutator and brushes that can reduce pump performance by increasing the electrical resistance of the brush-commutator interface. The pump motor has a nominal voltage rating. A power circuit is coupled to the pump motor for selectably providing an operating voltage and a boost voltage, wherein the boost voltage is greater than the nominal voltage rating. A controller selecting the operating voltage during an ordinary run cycle and selects the boost voltage during a clean-up cycle. The controller selects the clean-up cycle for a limited time that is sufficiently short to avoid damage to the pump motor from exceeding the nominal voltage rating and sufficiently long to create arcing between the commutator and brushes that reverses formation of the film.