Injection system Magneti Marelli 8P and Bosch Motronic MP5.1.1
The Magneti Marelli 8P fuel injection system is installed on engines with a displacement of 1.6 liters (BFZ), and Bosch Motronic MP5.1.1 is installed on 1.8 liter engines (LFY) and on 2.0 liter engines (RFV).
Both systems (ignition / fuel injection system) include a catalytic converter and an evaporative emission control system, and also comply with the latest emission control standards.
The fuel system in both injection systems is similar and works as follows. The fuel pump, immersed in the fuel tank, delivers fuel from the tank to the fuel injector through the filter. The fuel pressure in the system is controlled by a pressure regulator. The regulator allows excess fuel to return to the fuel tank when the pressure in the fuel system is exceeded.
The electrical control system consists of an ECU along with the following sensors:
- throttle potentiometer - tells the ECU the position of the throttle valve open or closed;
- coolant temperature sensor - reports engine temperature to the ECU;
- intake air temperature sensor - tells the ECU the temperature of the air passing through the throttle;
- lambda sensor - informs the ECU of the oxygen content in the exhaust gases;
- crankshaft position sensor - tells the ECU the engine speed and crankshaft position;
- manifold absolute pressure sensor - tells the ECU the vacuum in the intake manifold;
- vehicle speed sensor - tells the ECU the vehicle speed;
- a knock sensor installed in the cylinder block is used to detect the onset of knocking or early ignition (this allows the ECU to select the optimum ignition timing for prevailing engine operating conditions without risk of engine damage). It is installed only in the Motronic system.
All information from the sensors is analyzed by the ECU, and on this basis, the ECU determines the appropriate ignition timing and fuel mixture. The ECU controls the fuel injectors by changing the pulse width, i.e. the length of time the nozzle is open to provide a richer or leaner mixture.
The ECU also controls idle speed. To do this, there is a motor that controls the position of the throttle.
The ECU also controls the composition of the exhaust gases and the fuel vapor control system.
The electric heating element is located in the throttle body.
If there is an error in any of the data received from the sensor, the ECU enters standby mode. In this case, the ECU ignores the incorrect sensor signal and assumes a pre-programmed value that will allow the engine to continue running (albeit with less efficiency). If the ECU enters the backup mode, then the alarm lamp on the instrument panel will light up and the fault will be recorded in the ECU memory. After this, a full test of the engine management system must be carried out using a special electronic diagnostic test stand, which is simply plugged into the diagnostic socket of the system, located near the fuse box on the panel.
Bosch Motronic MP5.2 injection system
The Bosch Motronic MP5.2 injection system is installed on engine models with a displacement of 2.0 liters without a catalyst (R6E engine).
The MP5.2 injection system is similar to the MP5.1.1 system described above, however, it does not have a lambda sensor and a fuel vapor emission system.