Hi everyone - sorry if it’s a dosey t**t question, but I’m having trouble finding what on earth the ignitor (igniter?) unit does. I know the engine won’t fire up without it.
Anyone know (with a vague degree of precision!) what the thing does?
Cheers 
Neil
The igniter makes and breaks the the primary ignition circuit to the ignition coils. It’s the electronic equivalent of a set of points.
It’s a unit containing power transistors which sits between the ECU and the ignition coilpacks. The ignition timing signals coming out of the ECU do not have sufficient power to drive the coilpacks directly, so the igniter amplifies the signals to turn the coils on and off.
Although it’s a separate part in the original 1.6 cars, the igniter transistors were moved into the coilpacks themselves when the 1.8 came along.
Thanks very much!!!