Engine Start-Up

This is an OPEN LOOP mode.

The following actions occur when the starter motor is engaged:

- If the PCM receives an engine rotation signal, from the crankshaft position sensor, it will ENERGIZE the Auto Shutdown (ASD) relay and the fuel pump relay. The auto shutdown relay will supply the fuel injectors, ignition coils, and the alternator field with battery voltage. The fuel pump relay supplies the fuel pump and the oxygen heater with battery voltage.

- If the PCM does not receive an engine rotation signal from the crankshaft position sensor, the ASD relay will be DE-ENERGIZED after approximately one second.

Once the ASD relay is ENERGIZED, the PCM:

- Will supply the injectors with a ground path, firing all ten injectors until the PCM determines crankshaft position

- Will monitor coolant temperature, barometric pressure (at engine cranking only), and the number of engine revolutions since the cranking was initiated. The PCM and ICM uses these inputs to calculate the injector pulse width.

- Will monitor crankshaft and camshaft position, coolant temperature, manifold absolute pressure, and throttle position. The PCM uses these inputs to calculate the correct ignition timing.