Patent ID: 8622047

Claim:
A method of cleaning a fuel pump pressure control function valve of a high pressure fuel pump, the fuel pump pressure control function valve having an orifice linking a first high pressure region having a normal operating pressure and a second low pressure region, and a closing member biased to close the orifice when fuel pressure in the first region is below a threshold of the pressure control function valve, being set to be below the normal operating pressure, the pressure fuel pump having a safety valve being mechanical biased to block the flow of fuel from the high pressure region to the low pressure region and opening at a predetermined safety threshold within an overpressure condition, the method comprising: increasing the pressure in the first region to an overpressure condition, thereby causing the closing member to be moved to open the orifice such that a rapid flow of fuel occurs from the first region to the second region and thereby cleaning the fuel pump pressure control function valve.