With the pump-injector injection system, each engine cylinder has a pump-injector unit which generates the high pressure for the injection process and injects the right amount of fuel at the right time. Since these units are installed in the cylinder head, there is no need for the high-pressure lines necessary with the conventional distributor-type injection pump. The advantages of pump-injector technology are reduced combustion noise, lower pollutant emissions and more economical fuel consumption together with a higher power output.