Attention: Due to the large number of modifications of MPI fuel injection systems installed on vehicles, this chapter provides information that is relevant to all vehicles on which this system is installed. We recommend that a more thorough check and repair of system elements be carried out in specialized service centers.
The operation of the MPI fuel injection system is carried out using several components and parts: the fuel pump, which is located in the fuel tank, pumps fuel from it and supplies it through the fuel filter through the distribution line to the injection valves (injectors). The injection valves are controlled by the control unit, which calculates the injection timing and the amount of fuel injected. When current flows through the solenoid winding, the injection valve needle retracts and fuel is injected (when the current circuit is broken, the spring returns the needle, and the valve closes). The injection valves are controlled separately in the ignition sequence. The pressure regulator, located on the distribution line, maintains a constant pressure in the fuel system.
The intake air is cleaned in the air filter, in the housing of which there is an air mass meter that transmits information to the control unit. Pulse signals from other sensors also come there, for example, an atmospheric pressure meter or an intake air temperature sensor.
Cleaned air is supplied to the engine through the intake manifold.
Lambda probe (oxygen sensor) serves to measure the oxygen content in the exhaust gases and transmit information to the control unit in the form of voltage.
The throttle body contains a throttle valve that regulates the amount of air through the gas pedal. There is also an idle speed control mechanism in the throttle body that regulates the air supply bypassing the throttle. The position sensor of the adjusting motor and the idle speed switch are installed on the idle speed controller.
The layout of the elements of the MPI fuel injection system
The location of the elements of the fuel injection system on the car
1 - relay of the air conditioning system;
2 - air flow sensor;
3 - coolant temperature sensor;
4 - crankshaft position sensor;
3 - servomotor (ISC);
6 - start inhibit switch;
7 - temperature sensor;
8 - solenoid valve for fuel tank ventilation;
9 - solenoid valve (version);
10 - camshaft position sensor;
11 - nozzle (injection valve);
12 - transistor of the ignition system;
13 - output adjustment of the ignition timing;
14 - fuel pump test output;
15 - fuel pressure control relay;
16 - oxygen sensor;
17 - transmission selector;
18 - plug of the self-diagnosis system;
19 - relay of the engine control module;
20 - engine control module (MPI);
21 - vehicle speed sensor (pointer).
The location of the elements of the injection system on the car