The fuel pump, submerged in the fuel tank, delivers fuel through a filter to the fuel distributor. The fuel supply pressure is controlled by a valve built into the fuel pump. At the outlet of the fuel filter there is a T-piece, one end of which is connected to the pressure regulator, and the other to the fuel distributor. The regulator maintains the operating pressure in the fuel distributor, and excess fuel is drained through the return hose back into the fuel tank.
The electrical system includes an electronic control unit (ECU) and the following sensors:
- throttle potentiometer - a signal to the computer about the position of the throttle and the speed of its opening and closing;
- engine coolant temperature sensor;
- air temperature sensor passing through the throttle body;
- oxygen sensor (Lambda probe) - informs the computer about the oxygen content in the composition of the exhaust gases;
- crankshaft speed sensor - notifies the computer about the speed and position of the crankshaft;
- intake manifold absolute pressure sensor - informs the ECU about the engine load by vacuum in the intake manifold;
- knock sensor - informs the ECU about early ignition in the cylinders;
- vehicle speed sensor.
The electronic control unit analyzes the signals from all listed sensors and determines the appropriate ignition timing and composition of the air-fuel mixture.
The system controls idling with a stepper motor mounted on the throttle. The electric motor is connected to a rod that controls the change in the section of the channel through which air passes, bypassing the closed throttle. 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 the removal of fuel vapors.
If the readings of any sensor go beyond the expected values, then the ECU does not receive its signal and uses some constant value stored in its memory instead of the current value of the parameter. In this case, the engine continues to work, although with less efficiency. If such a situation occurs, the control lamp lights up in the instrument cluster, and the corresponding fault code is entered in the computer memory.
If the indicator lamp in the instrument cluster lights up indicating a malfunction, the type of malfunction must be determined as soon as possible. To do this, you will need a special device that reads fault codes and connects to the diagnostic connector of the computer.