Century V6-173 2.8L VIN W FI (1987)
Direct Ignition Module: Description and Operation
PURPOSE
The Direct Ignition System (DIS) module monitors the crank sensor signals and based on these signals sends a reference signal to the Electronic
Control Module (ECM) so that correct spark and fuel injector control can be maintained during all driving conditions.
OPERATION
During cranking, the DIS module monitors the "sync-pulse" to begin the ignition firing sequence and below 400 rpm the module controls spark
advance by triggering each of the two coils at a pre-determined interval based on engine speed only. Above 400 rpm the ECM controls the spark
timing (Electronic Spark Timing (EST)) and compensates for all driving conditions. The DIS module must receive a "sync-pulse" and then a crank
signal in that order to enable the engine to start.
The DIS module is not repairable. When a module is replaced, the remaining DIS components must be transferred to the new module.