Knock Sensor Module: Description and Operation

Fig. 24 Ignition System Component Layout:

The knock sensor control unit, which is mounted in the cowl at the right rear of the engine compartment, actively controls "Knock" allowing calibration of the ignition timing for normal operating conditions, while eliminating the danger of knock or detonation due to influences by engine heat, load, fuel quality or engine deposits.
The TCI-h ignition system with a knock control differs from the basic TCI-h system by the addition of the knock sensor and knock sensor control unit. With this system, the distributor has no centrifugal or vacuum advance mechanisms. All adjustments to the ignition timing are controlled electronically by the knock sensor control.

Knock Sensor Regulation:

When the knock control unit recognizes a knock condition, the ignition point for that individual cylinder will be retarded 3.0°. If the knocking stops, the timing will be advanced in increments of .33° back to programmed values.
If knocking continues, the ignition point can be retarded up to 15° for an individual cylinder, however, it is limited to a maximum of 9° difference between cylinders.
The knock sensor control unit incorporates a fault memory which recognizes and displays faults. The fault memory may be communicated using a "LED" test light at the ignition distributor electrical plug.