DELCO-REMY MISAR Ignition: Operation
The controller assembly receives input signals from the crankshaft position sensor (crankshaft position and RPM), coolant temperature sensor, manifold (engine vacuum), and atmosphere.
The controller assembly, based on these signals, decides how much ignition advance is required for best engine performance under any given engine operating condition. The controller assembly then sends a signal to the distributor to fire the spark plugs.
The "CHECK IGNITION" indicator light will come on under the following conditions: Any time ignition switch is turned to the "START" position. If electrical voltage is low. When checking reference timing and the reference timing connector is grounded. If the controller assembly fails to advance spark timing.