The fuel pump, immersed in the fuel tank, supplies fuel through the filter to the fuel distributor. The fuel supply pressure is regulated by a valve built into the fuel pump. At the outlet of the fuel filter there is a T-shaped tee, one end of which is connected to the pressure regulator, and the other to the fuel distributor. The regulator maintains the working pressure in the fuel distributor, and excess fuel is drained back into the fuel tank through the return hose.
The electrical system includes an electronic control unit (ECU) and the following sensors:
- throttle potentiometer - signal to the ECU about the position of the throttle valve and the speed of its opening and closing;
- engine Coolant Temperature Sensor;
- throttle Body Air Temperature Sensor;
- oxygen sensor (lambda probe) — informs the ECU about the oxygen content in the exhaust gases;
- crankshaft speed sensor - informs the ECU about the speed and position of the crankshaft;
- manifold Absolute Pressure Sensor - informs the ECU about the engine load based on the vacuum in the intake manifold;
- knock sensor - informs the ECU about early ignition in the cylinders;
- vehicle speed sensor.
The electronic control unit analyzes signals from all of the listed sensors and determines the appropriate ignition timing and the composition of the fuel-air mixture.
The system controls idle speed using a stepper motor mounted on the throttle valve. The motor is connected to a rod that controls the change in the cross-section of the channel through which air passes bypassing the closed throttle valve. The same channel is used during a cold start of the engine to supply additional air to the intake manifold.
The ECU controls the exhaust system and fuel vapor removal.
If the readings of any sensor go beyond the expected values, the ECU does not accept its signal and instead of the current value of the parameter, it uses a constant value stored in its memory. In this case, the engine continues to operate, although with less efficiency. When such a situation occurs, a control lamp lights up in the instrument cluster, and a corresponding fault code is stored in the ECU memory.
If the control lamp in the instrument cluster lights up indicating a malfunction, it is necessary to determine the type of malfunction as soon as possible. This will require a special device that reads the malfunction codes and is connected to the diagnostic connector of the ECU.