Electronic Fuel Injection: Operation: Notes

The amount of air entering the engine is measured by monitoring the intake manifold absolute pressure, the intake air temperature, and the engine speed. This information allows the electronic control unit to compute the flow rate of fuel required to achieve the desired air/fuel ratio for the particular engine operating condition. Each of the injector groups are activated once for every revolution of the camshaft or once for every two revolutions of crankshaft. The ECU converts the multi-variable information into an injector pulse width signal which opens the injectors for the proper duration and at proper time with respect to cylinder firing sequence.