The electronic injection system of MAZDA 323 injects fuel into the intake pipe before the intake valves depending on the engine condition.
Fuel is drawn from the tank by an electric fuel pump and supplied through the fuel filter and distribution line to the injection valves.
Air is sucked in by the engine through the air filter and intake manifold and is measured by the air flow meter. The air flow meter housing contains a flap that is deflected by the air flow. The flap position acts as a parameter for determining the air flow. The corresponding signal is sent to the control device from the flap potentiometer.
The control unit regulates the injection time according to the amount of air and the engine speed. With a longer opening of the injection valve, more fuel is injected per revolution of the crankshaft. The control unit is located in the housing in the car interior behind the center console.
Additional sensors and components ensure the correct air/fuel ratio in all situations.
- The air flow meter is located directly on the air filter. It reports the instantaneous air volume to the control unit.
- The throttle position sensor is located directly on the throttle shaft. It reports the current throttle position to the control unit. The control unit, based on the data received from the air flow meter and the throttle position sensor, determines the optimal amount of fuel for the corresponding load level.
- Idle speed control valve (electromagnetic valve) regulates the air supply to the throttle valve environment. Thanks to this, the engine speed is stabilized, especially during the warm-up phase.
- Lambda probe (oxygen sensor) measures the oxygen content in the exhaust gases and sends a corresponding electrical signal to the control unit. Based on this, the control unit changes the composition of the working mixture so that the exhaust gases are optimally burned in the catalytic converter (catalyst).
- The temperature sensor measures the temperature of the coolant on the cylinder head. It transmits data to the control unit. The control unit matches the quality of the working mixture with the temperature, due to which the engine operates stably in all temperature conditions.
- The fuel tank ventilation valve is controlled depending on the engine condition. The released fuel vapors in the tank are accumulated by the adsorber with activated carbon and are discharged through the valve for afterburning. Thanks to the adsorber with activated carbon, gasoline vapors are mostly used for good and do not enter the environment.
Caution! When working on the fuel injection and supply system, certain cleanliness rules must be followed, see Chapter Power supply system, carburetor, fuel injection system, Chapter Cleanliness rules when working with the power supply system.