Optical Ignition System: 1.8L

Optical ignition system consists of a distributor, spark plugs, ignition coil, power transistor, Electronic Control Module (ECM), high tension cables and wiring. Distributor incorporates power transistor, ignition coil and crankshaft position sensor. ECM detects engine operating conditions from various sensor signals, and regulates ignition timing based on these signals.

With ignition on, battery voltage is applied to ignition coil primary winding. As distributor shaft rotates, ignition signals are transmitted from ECM to power transistor. These signals activate power transistor, causing ignition coil primary winding current to either repeatedly flow from ignition coil negative terminal through power transistor to ground, or to be interrupted. This action induces high voltage in secondary winding of ignition coil. From coil, secondary winding current flows through distributor and spark plug to ground, causing ignition in each cylinder.