9-3 (9440) L4-2.0L Turbo (2.0 HOT) (2003)
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Consequently, ignition will take place in both cylinders and in the same way, ignition will take place in cylinders 2 and 3 at the same time.
In order to synchronise the firing order, ECM must detect the result (combustion or not) after the simultaneous spark in cylinders 1/4 and 2/3
respectively.
This is achieved in the following way:
Suppose a spark has been generated in cylinder 1 and 4. CDM will detect this because it is connected to the ignition trigger line of the respective ignition
coils. CDM analyses the ionization signal from ignition coil pin 4 for cylinder 1 pin 16 and cylinder 4 pin 15 on CDM.
The cylinder in which combustion has taken place will produce a powerful ionization signal.
If combustion takes place in cylinder 1 then CDM will send a pulse from pin 4 to ECM pin 20(B) and from CDM pin 11 to ECM pin 21(B) if in cylinder
4. With regard to cylinders 2 and 3, if combustion takes place in cylinder 2, a pulse will be sent from CDM pin 11 to ECM pin 21(B) and cylinder 3 a
pulse from CDM pin 4 to pin 20(B) on ECM.
When combustion signals arrive on ECM pins 20(B) and 21(B), the firing order and fuel injection will be synchronised.
