Knock Signal

Knock Signal:

The knocking signal informs the ECM when knocking occurs in any of the cylinders.

By measuring changes in the ionization current which is recorded individually for each cylinder just before or just after ignition, the electronic circuitry in the ignition discharge module (ignition cartridge) can convert the changes in the ionization current to variations in the signal which goes from pin 7 of the module to pin 44 of the ECM.

On the basis of the knocking signal, the ECM can counteract further knocking by changing the charging pressure, ignition timing and fuel injection times.