Ignition System: Description and Operation

Ignition System:

The ignition system includes an induction type ignition coil, igniter assembly, a single, twin or triple pick-up distributor, and electronic spark advance (ESA) circuitry located in the TCCS ECU. A specially constructed distributor cap, rotor and spark plugs are used to insulate higher secondary voltages produced by the ignition coil. There are no centrifugal or vacuum advance mechanisms, as spark timing is controlled entirely by the ESA.

Timing signals are generated through magnetic induction by the pick-up coils, as in conventional electronic ignition systems, but these signals are transmitted to the TCCS ECU rather than to the igniter assembly. The TCCS ECU is programmed with optimum ignition timing values for all operating conditions. It uses signals from the pick-up coils to compute crankshaft position and signals from other sensors to compute engine and vehicle operating conditions, then adjusts ignition timing by controlling the switching function of the igniter assembly. The igniter assembly controls current switching through the ignition coil primary circuit, and therefore induction of secondary spark voltage.