Engine Ignition - V8 S/C 5.0L Petrol (G2796644): Operation

The ignition coil on-plugs are supplied with electrical power from the PCM  relay in the EJB  . The PCM  controls the operation of the PCM  relay.

The PCM  sends a separate signal to each ignition coil on-plug to trigger the power stage switching. The PCM  calculates the dwell time from the battery voltage and engine speed, to make sure a constant energy level is produced in the secondary coil each time the power stage is switched. This ensures sufficient spark energy is available without excessive primary current flow, which avoids overheating and damage to the ignition coils.

The PCM  calculates the ignition timing for individual cylinders from:

• Engine speed
• Camshaft position
• Engine load
• Engine temperature
• The knock control function
• The shift control function
• The idle speed control function.