DIESEL ENGINE

PROBLEM TO BE SOLVED: To provide a diesel engine capable of determining failure of a rack sensor in an early stage after a key switch is charged to a starter motor drive position.SOLUTION: A diesel engine comprises: a key switch 1; a starter motor 3 linked to a battery 2 through the key switch 1; a rotation sensor 4 for detecting engine rotation; a rack sensor 6 for detecting a rack position of a fuel metering rack 5a of a fuel injection pump 5; and a failure determination device 7 to which the key switch 1, the rotation sensor 4 and the rack sensor 6 are linked. After the key switch 1 is charged to a starter motor drive position 8,on the basis of the fact that output of the rotation sensor 4 is detected and output variation of the rack sensor 6 by vibration in cranking is not detected, the failure of the rack sensor 6 is determined by the failure determination device 7.