The technical characteristics of the engines of trucks, buses, minibuses and cars, the main parameters and operational properties of the engines are presented. Faults and diagnostic parameters of mechanical and hydro-gas-aerodynamic systems of engines are described. Components of torque control systems, air supply and supply, fuel injection, self-formation and fuel spraying. Accumulator fuel injection systems with electrohydraulic and piezoelectric nozzles and injection systems with pump-nozzles are given. Varieties of fuel injection systems and their components are considered. Electronic fuel injection systems with in-line fuel injection pump, distributing fuel injection pump, individual fuel injection pump and common rail system, instruments and components used in these systems are described.