Unlike other systems, the Motronic system uses sequential fuel injection. This means that the injectors open and the fuel is injected in accordance with the operation of the cylinders.
The idle speed is controlled by a stepper motor of the throttle valve. A special heating film is used on the mass air flow sensor. The advantage of using the film is that there is no need to clean it from dirt by heating it, which is required when using a conventional filament.
The use of exhaust gas afterburning by feeding additional air to the exhaust valves reduces the amount of unburned particles in the exhaust gases. The exhaust gas recirculation system allows, depending on the engine operating mode, to feed a certain amount of exhaust gas into the intake manifold again. This reduces the content of exhaust gas oxides.
The throttle pipe is part of the fuel injection control mechanism. The main task of the injection control mechanism is to maintain stable engine speed at idle under any operating conditions and engine loads, including when additional equipment, such as air conditioning, is turned on. The throttle potentiometer transmits information to the control unit about the angle of its opening. The control unit opens or closes the throttle valve using the actuator motor, thus maintaining the nominal idle speed.
The throttle position controller consists of an actuator with a gear and a return spring. The throttle potentiometer is located on its axis and is the source of the signal for the engine control unit about the throttle opening angle. The second potentiometer is a backup and its signal is used by the engine control unit if the main potentiometer fails.
The electronic fuel injection system has its advantages, which are as follows:
- a) precise dosing of the amount of fuel in each engine operating mode, which ensures lower gasoline consumption while maintaining good dynamic performance;
- b) reduction of the amount of harmful exhaust gases as a result of precise fuel metering and purification of exhaust gases (EG) using a catalyst;
- c) self-diagnosis of the control unit, which allows you to find the fault faster. The injection system is equipped with a "memory" where errors during the operation of the car are recorded. If failures occur in the ignition or injection system during operation, they are recorded. If failures occur in the engine operation, you can get a printout of faults in a specialized workshop for a fee, so that you can eliminate this or that defect yourself if necessary.
The microprocessor that controls the engine is a small, fast computer. It determines the optimum ignition timing, the moment of fuel injection, and the volume of fuel injected. At the same time, the microprocessor's actions are coordinated with the control units of other vehicle systems, such as the gearbox control unit or the anti-theft system.
Precautionary measures
Caution! The fuel system is under pressure. Before disconnecting the fuel system hoses, wrap the hose junction with a rag and only then carefully remove the hose, releasing the pressure.
Fuel vapors are toxic and highly flammable. Avoid contact with skin. Wear protective goggles. Ensure adequate ventilation of the workplace. Fire hazard! Equip the workplace with a fire extinguisher.
To avoid injury or damage to the fuel injection system or the fuel system as a whole, the following safety precautions are recommended:
- Do not touch or remove high voltage wires while the engine is running or when the starter is engaged.
- Connect and disconnect the wires of the injection and ignition systems only with the ignition off. The same applies to the wires of the measuring devices used to perform measurements on these systems.
- Persons with a pacemaker should not be allowed to perform work on the electronic ignition system.
- When checking compression, fuel injection must not be performed.
Attention! When working on the injection system, general safety and cleanliness rules must be observed (see the section "Fuel system").