The MotorVac CarbonClean System II two-line cleaning system connects to the engine through vehicle-specific adapters, temporarily taking the place of the vehicles fuel supply system. The system passes a potent mixture of CarbonClean detergent and gasoline through the components of the fuel system. During the first phase with the engine off, the System removes gum, varnish and build up of other deposits in the fuel rail, injector screens, and pressure regulator areas, filtering out the contaminant.