Ignition System

The Motronic ignition system 2.10.3 is a conventional electronic ignition system with ignition coil, distributor with rotor, distributor cap and ignition leads. Firing order is 1-3-4-2.
In the distributor there is a camshaft position sensor (hall sensor), which with the assistance of a slotted rotor with one slot gives information to the control module when cylinder 1 is in position for combustion. When cranking the start motor and at engine speeds up to approx. 600 rpm, the control module utilizes a fixed ignition timing of 5° BTDC. At engine speeds over approx. 600 rpm and when the throttle position sensor indicates idling speed, the control module follows an ignition timing program which is at 10° BTDC if there is no load on the engine. In connection with up or downshifting on cars with automatic transmission, a torque limitation will occur through a retardation of the ignition by up to 12°.
The ignition timing is calculated in the control module with help of the following information:
- Engine speed (Td)
- Engine load (Tq)
- Possible knocking