Fuel injection system for a combustion engine

The device has a control piston (50) in a control pressure chamber (52) connected to an injection valve element (28) dividing the control pressure chamber into two sub-volumes connected together via a choke point. With a second control valve (70) closed, if the control pressure chamber is separated from a relief chamber (24) a lower force acts on the control piston in an injection valve element (28) closing direction than if the valve is open.