Starting Mode (Port and TBI Injection)

When the ignition is switched On, the ECM energizes the fuel pump for two seconds and pressure is built up in the fuel rail. The ECM then checks the coolant temperature sensor, the TPS and crank signal and determines the proper air/fuel ratio for starting.
The ECM controls the air/fuel ratio by changing how long the injectors are turned on and off. This is accomplished by ``Pulsing'' the injectors for short periods of time.