Modes Of Operation: Starting

When ignition switch is first turned on, the ECM will turn fuel pump relay on for 2 seconds, this allows the fuel pump to build up pressure in TBI unit. The ECM then checks coolant temperature sensor, throttle position sensor, and crank signal to determine proper air/fuel ratio for starting.

The ECM controls the amount of fuel delivered in the starting mode by changing how long injectors are turned on or off. This is done by "pulsing" the injectors for very short periods of time.