Skylark L4-138 2.3L DOHC VIN D MFI QUAD 4 (1989)
Ignition Control Module: Description and Operation
Ignition Module Operation
This IDI module monitors the crank sensor signals and based on these signals sends a reference signal to the ECM so that correct spark and fuel injector
control can be maintained during all driving conditions. During cranking, the DIS module monitors the "sync pulse" to begin the ignition firing sequence
and below 700 rpm the module controls spark advance by triggering each of the two coils at a pre-determined interval based on engine speed only.
Above 700 rpm the ECM controls the spark timing (EST) and compensates for all driving conditions. The IDI module must receive a "sync pulse" and
then a crank signal in that order to enable the engine to start. The IDI module is not repairable. When a IDI module is defective, the module is replaced
as a separate component.
