MOTORCRAFT Solid State Ignition System: Operation
The electronic control unit and ignition coil are turned on whenever the ignition switch is in the "START" or "ON" position. When the engine begins turning the distributor shaft, the trigger wheel rotates with it. As each tooth passes the pick-up coil, it interrupts the magnetic field around the pick-up coil. This continual build-up and collapse of the magnetic field provides a signal to the control unit. The control unit receives this signal and turns the power to the ignition coil's primary circuit off and on as each tooth passes the pick-up coil.
The collapse of the magnetic field in the ignition coil primary circuit induces a high voltage surge in the secondary. This causes current to flow from the coil to the distributor, rotor, cap and spark plug wires. Ignition timing is constantly changed by the control unit, the Micro Computer Unit (MCU), and vacuum and centrifugal advance mechanisms according to engine operation.
SOLID STATE IGNITION SYSTEM NOTES
When disconnecting wire from spark plug or distributor cap, twist rubber boot slightly to loosen. Grasp boot (not wire) and pull off with steady, even force.
When disconnecting control unit connectors, pull apart with firm, straight pull. Do not attempt to pry apart with screwdriver. When connecting, press together firmly to overcome hydraulic pressure caused by the silicone dielectric compound. If connector locking tabs weaken or break off, it is unnecessary to replace connector. Just press firmly together and bind with electrical tape or a harness tie strap. This should assure a good connection.