A8: Engine Performance

Spark plug wires and the distributor; each cylinder has its own coil mounted directly on the plug.

Each coil fires two companion cylinders simultaneously; one fires on compression (useful) and the other on exhaust (wasted).

Dwell is the time current flows through the primary winding to build (saturate) the magnetic field before the coil fires.

The ignition coil; the rapid collapse of the primary field induces high voltage in the secondary winding.

Normal combustion and a properly operating engine with correct heat range and mixture.

A rich air-fuel mixture or excessive idling; carbon fouling from incomplete combustion.