Ignition System

IGNITION SYSTEM
The ignition system of the MOTRONIC 2.10.2 is a conventional electronic system with ignition coil, distributor with rotor arm, distributor cap and HT leads. The firing order is 1-3-4-2.

Inside the distributor is a camshaft position sensor (Hall-effect sensor) which, by means of a slotted rotor with a gap, tells the control module when cylinder No. 1 is in the ignition position.

When the engine is being turned over by the starter motor and at speeds up to about 600 rpm, the control unit uses a fixed ignition point of 5° BTDC. At engine speeds above about 600 rpm and when the throttle position sensor indicates that the engine is idling, the control module sets the ignition timing at 10° BTDC as long as the engine is running under no-load conditions.

In conjunction with upshifts or downshifts on cars with automatic transmission, engine torque is limited by retarding the ignition by up to 12°.

Ignition timing is determined by the control module on the basis of the following information:
^ Engine speed (Td)
^ Engine load (Tq)
^ Knocking (if occurring)