Ignition System - 3.0L Optical: Operation: Notes

The SMEC receives engine speed and crankshaft position signals from the optical distributor. Microprocessor determines correct timing of ignition event and signals ignition coil to produce an electrical impulse firing appropriate spark plug. SMEC is located on left front fenderwell. Connection to other fuel/ignition components is by 14-pin and 60-pin connectors.

Amount of electronic spark advance provided by SMEC is determined by 3 input factors, coolant temperature, engine RPM and available manifold vacuum.

Manifold Absolute Pressure (MAP) sensor is mounted under hood on dash panel. Distributor mounted optical pick-up assembly triggers onset of fuel injection and establishes base timing point.

Optical distributor is connected to SMEC system by a lead wire which is plugged into base of distributor and held in place with lead wire clamp.