Electronic Engine Controls

ELECTRONIC ENGINE CONTROLS

The electronic engine controls consist of the following:
- Powertrain control module (PCM)
- Cylinder head temperature (CHT) sensor
- Camshaft position (CMP) sensor
- Crankshaft position (CKP) sensor
- Mass air flow (MAF) sensor
- Heated oxygen sensor (HO2S)
- Catalyst monitor sensor (CMS)
- Knock sensor (KS)

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 CHT sensor:
- sends the PCM a signal indicating cylinder head 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 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 KS:
- is used to detect engine detonation.
- sends a voltage signal to the PCM.
- is able to provide a signal which retards the ignition timing, as necessary.