Legacy Sedan 2WD F4-2.2L SOHC (1990)
Ignition Coil: Description and Operation
Ignition Coil Testing
PURPOSE
Transforms battery voltage into ignition voltage and delivers it in the form of a high voltage surge to the secondary ignition components.
LOCATION
On top of intake manifold.
CONSTRUCTION
The ignition coils contain two sets of copper wire windings around a soft iron core. The primary winding is made of a hundred or so turns of a
heavy gage wire. It is connected to the battery through the ignition relay. The secondary winding contains several thousand turns of wire wound
directly onto the iron core. The ratio of the number of wraps in the secondary winding to the number of wraps in the primary windings determines
the output voltage of the coil. The secondary winding is connected to the coil output towers (2) through the iron core.
OPERATION
When current flow in the primary winding is stopped (by the ignitor), the collapse of the magnetic field causes a voltage to be induced in the
secondary windings. Voltage flows out of the coil's (2) secondary terminal, through the ignition cable, into the spark plug and jumps the electrode
gap to ground causing a spark. The coil fires two cylinders simultaneously; one on the power stroke and one on the exhaust stroke.