XJS
The Marelli ignition system is a fully digital microprocessor-controlled system. System components consist of the ECU, distributor, 2 ignition coils, 2 amplifier units, TDC sensor, flywheel sensor, air sensor, coolant sensors and idle switch. The microprocessor, located within the ECU, contains basic ignition timing requirements for the engine.
XJ6
Ignition pulses are applied from a separate ignition amplifier to the ignition coil. The ignition coil generates high energy pulses for the spark plugs. The distributor does not have centrifugal or vacuum advance mechanisms. The distributor is only necessary to distribute spark to the proper cylinder.
Depending on engine speed and supply voltage, the dwell angle is changed and ignition voltage (energy) is adapted at that very instant, preventing unnecessary energy consumption by the ignition coil. Peak coil current is also prevented from flowing through the coil if engine is not running at a specific speed, thus preventing battery discharge and ignition coil overheating
Nov 27, 2009 at 7:17 AM
