A Technique for the Diagnosis of Malfunctions in Diesel Injection Systems

Many diagnostic parameters have been studied for the detection of malfunctions in two types of diesel injection systems: the unit injector and the distributor pump system. It has been found that the peak fuel pressure in the unit injector pressure chamber (measured by a strain gage mounted on the injector rocker arm), and the peak fuel pressure in the line near the injector on the distributor injection system are very useful parameters for fault diagnosis. Figures and charts relating the fuel peak pressure and engine speed have been developed to identify a healthy as well as a faulty injection system.