Sensors and actuators (executive mechanisms) of the injection system (Mazda 121 (3))

The crankshaft position sensor is screwed into the cylinder block next to the oil filter. It tells the control unit the engine speed.

The camshaft position sensor for the 1.3L engine is screwed into the camshaft drive chain housing, and for the 1.25/1.4L engines - into the cylinder head. It transmits the engine position to the control unit.

The throttle potentiometer transmits the angular position of the throttle valve to the control unit.

The idle mode switch transmits information to the control unit about the throttle position corresponding to the idle mode.

The coolant temperature sensor is a resistance with a negative temperature coefficient, i.e. as the temperature rises, the resistance falls.

The inlet air temperature sensor is also a resistance with a negative temperature coefficient.

The fuel tank ventilation system consists of a container with activated carbon and an electromagnetic valve. The container with activated carbon accumulates fuel vapors that are formed when the fuel in the tank is heated. When the engine is running, the fuel vapors are sucked out of the container with carbon and fed to the engine for afterburning.

(Original version of the article on the website: www.mazbook.ru)

Lambda probe (oxygen sensor) serves to control the catalyst. It determines the oxygen content in the exhaust gases and sends a corresponding voltage signal to the engine control unit.

The exhaust gas recirculation system, depending on the engine condition, directs a certain proportion of the exhaust gases into the incoming air flow. This reduces the exhaust gas temperature and the concentration of nitrogen oxide in the exhaust gases.

The idle air quantity control valve regulates the amount of air flowing past the throttle valve in idle mode. This ensures a constant idle speed, regardless of whether additional consumers, such as the power steering or the air conditioning compressor, are switched on.