Ignition System: Description and Operation

Ignition Circuit:

This vehicle uses an ECU controlled electronic ignition system. Components include:

^ Ignition coil.
^ Camshaft driven distributor with crank angle sensor.
^ Igniter.
^ Distributor cap and rotor.
^ High voltage resistor (radio static suppressor) spark plug and ignition coil wires.


The crank angle sensor is a photo-diode type that provides the ECU with signals regarding engine rpm and #1 cylinder TDC (crankshaft position). Together with other inputs, the ECU calculates ignition timing over the range of vehicle operating conditions.

An ECU controlled igniter is used as a switch to regulate current flow through the coil primary circuit. Each time current flow is interrupted, high voltage is induced in the secondary ignition circuit to fire the spark plugs. Except for the initial setting, timing is determined by the ECU.

A distributor cap, rotor and high tension wires are used to distribute sparking voltage to the correct spark plug at the appropriate time.