Intake air temperature sensor

The ECM inputs and outputs are shown in the following table.

Intake air temperature sensor

The intake air temperature sensor is located in the side of the inlet manifold. This sensor is of the negative temperature coefficient (NTC) type, designed to reduce its resistance with increasing temperature. The ECM receives a signal proportional to the temperature of the intake air. When used in conjunction with the signal from the manifold absolute pressure sensor the ECM can calculate the volume of oxygen in the air and adjust the quantity of fuel being injected to achieve optimum fuelling of the engine.

Injectors

The four fuel injectors are fitted between the pressurised fuel rail and inlet manifold. Each injector comprises of a solenoid operated needle valve and a specially designed nozzle to ensure good fuel atomisation.

The injectors are controlled in grouped mode with 2 & 3 being grouped and 1 & 4 being grouped, with the injectors in each group being operated alternatively. The ECM determines when to operate the injectors based on the signal it receives from the crankshaft position sensor.

The ECM provides an earth signal for the period the injectors are required to be open, the injector solenoids are energised and fuel is sprayed into the inlet manifold onto the back of the inlet valves. The ECM carefully meters the amount of fuel injected by adjusting the injector opening period (pulse width). During cranking, when the engine speed is below approximately 400 rev/min, the ECM increases the injector pulse width to aid starting. The amount of increase depends upon engine coolant temperature. To prevent flooding, the ECM periodically inhibits the operation of the injectors.