Ignition System: Description and Operation

Engine Ignition

Component Locations







In order for the correct firing order to be observed it should be noted that the correct cylinder numbering is, when viewed from the rear of the engine, the right-hand cylinder bank is numbered 5,3,1 and the left-hand cylinder bank is numbered 6,4,2.

The ignition system consists of an ignition coil for each individual cylinder located on each individual spark plug. This allows the ignition timing to be adjusted more rapidly and independently.

The crankshaft position (CKP) sensor signal is the basis for ignition timing calculations. The alternating voltage signal from the CKP sensor is converted by the engine control module (ECM). This digital signal is then used to position the closing time of the primary circuit of the ignition coil. The effective range for ignition timing control is increased by the fact that there are no rotating parts.

On the basis of engine speed and load inputs, the ECM determines the ignition timing. This function also takes other inputs into consideration such as engine temperature, throttle position, knock control and electronic transmission control inputs.

This ignition system allows the customer to drive the vehicle home if an ignition coil or ignition coil wiring harness failure occurs. In the event of a wiring harness failure between the ECM and the ignition coil, the ignition coil will fail instead of its fuse. This will allow the remaining ignition coils to continue to function.