Ignition System: Description and Operation

Ignition System (Motronic Engine Management):

The Bosch CIS-E Motronic engine management system ignites the air/fuel mixture in the combustion chamber to provide optimal performance, driveability and minimal emissions.
This system incorporates mechanical components for the distribution and electronic components to control the ignition timing.

Ignition System Schematic:

OPERATION
As the distributor shaft turns, the trigger wheel (mounted to the shaft) induces a signal in the Hall-effect sender. The signal is sent to the Motronic control unit which uses various input devices to calculate the precise ignition timing signal. The timing signal is sent to the power output stage which switches the coil primary circuit. This releases a precisely timed high voltage pulse, that flows through the coil wire to the distributor. The distributor rotor directs the voltage pulse, via the distributor cap, to the correct spark plug wire. At the spark plug it jumps a gap to reach engine ground. When the voltage pulse jumps the gap to ground, it creates a spark (ignition spark) strong enough to ignite the air/fuel mixture in the combustion chamber.

COMPONENTS OR SIGNALS
The Bosch CIS-E Motronic engine management system in this vehicle uses the following components or signals for ignition control:

NOTE: Some ignition related components or signals may be covered in a different section of the database. The correct section is indicated by a "refer to ...."

^ Cap and static shield
^ Coil wire
^ Distributor
^ Hall effect sender (refer to COMPUTERIZED ENGINE CONTROLS)
^ Ignition coil
^ Ignition timing sensor
^ Knock sensor signals (refer to COMPUTERIZED ENGINE CONTROLS)
^ Motronic control unit (refer to COMPUTERIZED ENGINE CONTROLS)
^ Power output stage (refer to COMPUTERIZED ENGINE CONTROLS)
^ Rotor
^ Spark plug wires
^ Spark plugs