Distributor: Description and Operation

Distributor Assembly:

PURPOSE
Directs high voltage ignition coil output to spark plugs in proper sequence (firing order). A rotor on the driven shaft acts as a rotary contact, directing ignition coil voltage to each spark plug terminal as it turns inside the distributor cap.

LOCATION
Rear of left cylinder head.

OPERATION
Distributor contains a trigger wheel that turns with the distributor shaft, and a stationary pick-up assembly. As the wheel rotates past the pick-up, signals are generated and interpreted by the ECU to determine crank angle (#1 cylinder TDC) and engine rpm. To calculate ignition timing, the ECU uses this input together with several others related to vehicle operating conditions. Except for the initial setting (basic distributor installed position), ignition timing is ECU controlled.