Viper V10-488 8.0L (1992)
-
Recognize an abrupt decrease in throttle position or MAP pressure as a signal of decreased engine output and vehicle deceleration.
-
Decrease injector pulse width to maintain proper air/fuel mixture.
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.
Engine Warm-Up
This is an OPEN LOOP mode.
During engine warm up, the PCM receives input from:
-
Air Conditioning control position
-
Battery voltage
-
Camshaft position (CMP) sensor
-
Engine coolant temperature (ECT) sensor
-
Manifold absolute pressure (MAP) sensor
-
Crankshaft position (CKP) sensor
-
Throttle position sensor (TPS)
The fuel injectors are fired by the PCM and ICM switching the ground path to control injection sequence and injector pulse width. The PCM
commands the ICM to adjust ignition timing according to input received from the speed sensor. The PCM controls the idle speed by adjusting the
automatic idle speed motor.
Ignition Switch Off
After the ignition switch is turned OFF:
-
No inputs are monitored.
-
All outputs are DE-ENERGIZED.
-
The PCM and ICM shut down.
Ignition Switch On