Ignition System: Description and Operation

Circuit Diagram:

SYSTEM TYPE
Ignition systems generate high voltage and direct it to spark plugs at each cylinder. Voltage must be high enough to jump the plug gap under compression, and it must be supplied at the correct time under a wide range of operating conditions. This vehicle uses a PCME (Powertrain Control Module) controlled electronic system.

COMPONENTS AND OPERATION
Distributor incorporates cap, rotor, ignition coil, igniter, and crankshaft position sensor into one assembly.

The crankshaft position sensor provides the PCME with signals regarding engine rpm and #1 cylinder TDC (crankshaft position). Together with other inputs, PCME calculates ignition timing over the range of vehicle operating conditions.

The PCME controlled igniter is the switch regulating current flow through coil primary circuits. Each time current flow is interrupted, high voltage is induced to fire the spark plugs. Except for the initial setting, timing is PCME controlled.

Distributor cap, rotor and high tension wires direct high voltage from the distributor assembly to each spark plug at the appropriate time as calculated by the PCME.