Attention! The fuel system is constantly under pressure, even when the engine is off.
The ECU Fuel Injection System is a self-tuning system that monitors and stores data to ensure optimum engine performance under varying loads. When the battery is disconnected, data is erased and to restore them, you must start the engine and keep it idling until the system adjusts. This process will be best performed by doing a road test for 15 minutes at 2500-3500 rpm.
FENIX 1B system
The Fenix IB system is a combined ignition and fuel injection system. When using inputs from various sensors, the electronic control device calculates the optimal fuel injector pulse width and ignition timing for engine operating conditions.
The electronic control device receives signals from the following sensors:
- engine speed sensor;
- manifold absolute pressure sensor;
- intake air temperature sensor;
- throttle position sensor;
- coolant temperature sensor;
- oxygen sensor.
The idle speed is controlled by an electronic control device through the idle speed control valve.
The oxygen sensor allows the electronic control device to control the composition of the fuel mixture within limits that allow the use of a catalytic converter.
The electronic control constantly changes the fuel mixture, idle speed and ignition timing to ensure efficiency in all operating conditions and reduce exhaust emissions.
BOSCH MONOPOINT MA 3.0 system
Bosch MA3.0 engine management system (ignition / fuel injection system) includes a catalytic converter and an evaporative emission control system, and complies with the latest emission control standards. The system works as follows. The fuel pump, submerged in the fuel tank, delivers fuel from the fuel 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.
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;
- microswitch - tells the ECU when the throttle is closed (i.e. when the throttle control pedal is not depressed);
- crankshaft position sensor - informs the ECU of engine speed and crankshaft position;
- vehicle speed sensor (on the gearbox).
MAGNETI MARELLI G5 and G6 systems
The Magneti Marelli engine management system is fitted to the XU5 engines. The operation of the system is similar to that of Bosch Monopoint MA 3.0. The electrical control system consists of the ECU along with the following sensors:
- manifold absolute pressure sensor - tells the ECU the vacuum in the intake manifold;
- crankshaft position sensor - informs the ECU of engine speed and crankshaft position;
- throttle potentiometer - tells the ECU the position of the throttle valve open or closed;
- coolant temperature sensor - reports engine temperature to the ECU;
- fuel mixture temperature sensor - informs the ECU of the temperature of the fuel mixture entering the engine;
- lambda sensor (oxygen) - informs the ECU of the oxygen content in the exhaust gases.
In addition, the ECU adjusts to the reduced battery voltage by changing the injector pulse width and changing the initial throttle position (additional engine) to increase idle speed.
To process signals from sensors, a digital method is used using data previously entered into the system's memory.
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, the alarm lamp on the instrument panel will light up and the fault will be recorded in the ECU memory. After that, it is necessary to carry out a full test of the engine management system using a special electronic diagnostic test stand, which is simply plugged into the diagnostic socket of the system.
Attention! When working on the fuel system, you must first remove the pressure in the system.