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Ignition spark/triggering

Ignition spark/triggering



Ignition/trigger pulses

The ignition coil in the MOTRONIC 2.8.1 consists of three ignition coils integrated in a module.

The three ignition coils are controlled by three ignition output stages, which in the MOTRONIC 2.8.1 are integrated in the control module.

On the basis of information on engine speed (Td) and load (Tq) supplied by the control module, pins 1, 20 and 21 ground or "open" the circuit to the integrated ignition coils. The output signal on pin 1 triggers the ignition coil for cylinders 1 and 4, the output signal on pin 20 triggers the ignition coil for cylinders 2 and 5, and the output signal on pin 21 triggers the ignition coil for cylinders 3 and 6.

The firing order is 1-2-3-4-5-6 and the control module adjusts the timing according to information on Td and Tq.

If knocking occurs in any of the cylinders, the timing is retarded in the cylinder concerned.

At idling speed the timing is controlled by a special timing program (Kennfeld or Map).

For information on ignition timing, see .

Measured with a voltmeter at 2000 rpm, the voltage across pin 1 and pins 37, 20 and 37, and across pins 21 and 37, is about 0.2 V.