primary coil for the first cylinder is grounded (via the ignition cassettes B+ intake) and 400 V is transformed up to a maximum of 40 kV in the secondary coil for cyl. 1. The same procedure is used for controlling the ignition timing of the rest of the cylinders. Ignition regulation At start the ignition point is 10° BTDC. To facilitate start when coolant temperature is below 0°C the ECU will ground each trigger line 210 times/second between 10° BTDC and 20° ATDC, at which a “multi spark” will appear. The function is active up to an engine speed of 900 RPM. At idle a special ignition matrix is utilised. Normal ignition point is 6°-8° BTDC. If the engine stalls e.g. cooling fan activation the ignition point is advanced up to 20 ° BTDC in order to increase the engines torque to restore the idle RPM. In the same way the ignition is retarded if the engines RPM is increased. When the TPS senses an increase in throttle opening the ECU leaves the idle ignition timing map and regulates the ignition timing in respect of load and engine speed. During engine operations the Ignition cassette continuously monitors the ion currents in the cylinders and sends a signal to the Trionic ECU, pin 44, in an event of knocking. The logic for this function rests solely in the ignition cassette and is adaptive to be able to handle disturbing fuel additives. The Trionic ECU is well aware which cylinder that has ignited and could hence cope with the information feed through one pin. The signal to pin 44 and ion current in the combustion chamber is related to each other, when this signal reaches a certain level the ECU interprets this as a knocking event and firstly lowering the ignition advance by 1,5° on this cylinder. If the knocking is repeated the ignition advance is lowered further 1,5 ° up to 12°. In case of the same lowering of the ignition timing advance in all cylinders the ECU adds a small amount of fuel to all cylinders. If knocking occurs when the MAP is over 140 kPa the knocking is regulated by switching both fuel injection matrix and ignition advance matrix. If this is not sufficient the charging pressure is lowered. This purpose of this procedure is to maintain good performance. If the signal between the ignition cassette and the ECU