Timing Light

A timing light connects to the battery and to the #1 spark plug wire to check ignition timing. A bright strobe light flashes in sequence with the firing of the #1 spark plug. One example is shown in Fig. 4-11. Guard against less expensive models with lights which are too dim to be seen in daylight.

An attractive feature of the more expensive models is an inductive pickup which just clamps on over the spark plug wire to get its signal, rather than needing a more positive connection.

An adjustable timing light is a more sophisticated instrument used to actually measure the timing and the advance and retard characteristics in engine crankshaft degrees. This type is only necessary for detailed analysis of the ignition system's function.

Fig. 4-11.

Timing light and electrical connections, including inductive pickup. Dial shown is found on sophisticated adjustable timing lights.