Ignition System: Description and Operation

DOUBLE IGNITION
This system uses a double six cylinder distributor with two spark plugs per cylinder and digital motor electronics (DME), to control engine operation. Using various sensor inputs, DME is able to monitor engine speed, load, temperature, and fuel mixture. These inputs are applied to preprogrammed "maps" to determine ignition output characteristics necessary for optimum fuel economy and performance. Timing is then advanced or retarded as necessary to comply with the ignition map.

Ignition triggering signal goes from DME control unit to two ignition final stages, which are installed on left-hand side of engine compartment. In each final stage, there is activation of a transistor, which interrupts secondary circuit of both ignition coils. This triggers parallel ignition by both ignition coils each time.

HALL SENDER
A hall sender is fitted to one half of double distributor. Hall signal is required for identification of cylinder #1 and in DME for assignment of both knock sensor signals as well as control of sequential fuel injection.

CENTRIFUGAL ADVANCE
Each distributor is fitted with centrifugal weights to ensure proper ignition rotor alignment with distributor cap. They operate in accordance with engine speed. They DO NOT effect ignition timing.