Electronic Engine Controls
The electronic engine controls consist of the following:^ Powertrain Control Module (PCM)
^ Throttle Position (TP) sensor
^ Idle Air Control (IAC) valve
^ Engine Coolant Temperature (ECT) sensor
^ Camshaft Position (CMP) sensor
^ Crankshaft Position (CKP) sensor
^ Mass Air Flow (MAF) sensor
^ Manifold Absolute Pressure (MAP) sensor (2.3L)
^ Intake Air Temperature (IAT) sensor
^ Heated Oxygen Sensor (HO2S)
^ catalyst monitor sensor
^ wheel speed sensor
The PCM:
^ accepts input from various engine sensors to compute the fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the entire engine operating range.
^ outputs a command to the fuel injectors to meter the appropriate quantity of fuel.
The TP sensor:
^ sends the PCM a signal indicating the throttle plate angle.
^ is the main input to the PCM from the driver.
The IAC valve:
^ controls bypass air around the throttle plate at low speeds.
^ is controlled by the PCM.
The ECT sensor:
^ sends the PCM a signal indicating engine temperature.
^ resistance decreases as coolant temperature increases.
The CMP sensor:
^ provides camshaft position information which is used by the PCM for fuel synchronization.
The CKP sensor:
^ sends the PCM a signal indicating crankshaft position.
^ is essential for calculating spark timing.
The MAF sensor:
^ uses a hot wire sensing element to measure the amount of air entering the engine.
^ sends the PCM a signal to determine the intake air mass. The PCM will then calculate the required fuel injector pulse width in order to provide the desired air/fuel ratio.
The MAP sensor:
^ measures manifold vacuum and converts it to an electrical signal. This provides the PCM information on engine load.
The IAT sensor (3.0L and 4.0L):
^ sends the PCM a signal indicating the temperature of the air entering the engine.
^ resistance decreases as temperature increases.
The HO2S:
^ has the ability to create a voltage signal dependent on exhaust oxygen content.
^ provides feedback information to the PCM used to calculate fuel delivery.
The catalyst monitor sensor:
^ has the ability to create a voltage signal dependent on exhaust oxygen content.
^ provides feedback information to the PCM used to calculate fuel delivery.
The wheel speed sensor:
^ sends a signal to the PCM indicating wheel speed.
Electronic Engine Controls - Supercharged Engine
Most of the supercharged engine electronic controls are similar to that of the non-supercharged 5.4L engine. These components are as follows:
^ Crankshaft Position (CKP) Sensor
^ Throttle Position (TP) Sensor
^ Idle Air Control (IAC) Valve
^ Mass Air Flow (MAF) Sensor
^ Intake Air Temperature (IAT) Sensor - Air Cleaner
^ Heated Oxygen Sensors (HO2S)
There are also three controls that are unique to the supercharged engine. These are as follows:
^ Barometric Pressure (BARO) Sensor
^ Intake Air Temperature (IAT) Sensor - Manifold
^ Supercharger Bypass Vacuum Solenoid
^ Supercharger Bypass Vacuum Solenoid - Actuator
Supercharger Bypass Vacuum Solenoid and Actuator
The Supercharger Bypass Vacuum Solenoid will bleed off boost during sudden throttle closing. This prevents damage that can occur if the throttle is quickly closed while the engine is still under heavy boost. The solenoid is located on the upper LH side of the engine. The solenoid uses engine vacuum to operate a actuator and linkage that connects to the pressure bleed off valve. The actuator is located near the solenoid and is connected to it by a vacuum line.
Barometric Pressure (BARO) Sensor
The BARO sensor is located on the upper LH side of the engine and is used to measure current barometric pressure.
Intake Air Temperature (IAT) Sensor - Manifold
The IAT sensor located in the manifold is located in the rear of the intake manifold, behind the supercharger. This additional sensor is needed due to the increase in air temperature caused by the supercharger compressing of the intake air.