Cold Starting

Start recognition and (cold) start enrichment have been changed for the M1.1 system. The M1.1 Motronic Control Unit has a programmed temperature related start recognition speed and no longer depends on a signal from terminal 50 (starter to Motronic Control Unit).





Another obvious difference to the previous system is the deletion of the cold start valve. Cold starting enrichment now takes place via the injectors in three phases.

1) During cranking, additional fuel is injected for the first five revolutions of the crankshaft. This fuel is injected several times per revolution to increase fuel dispersion.

Ignition timing is controlled by the Motronic system on the basis of cranking speed and initial temperature. It is adjusted simultaneously with the fuel quantity.

2) After five revolutions, the injected fuel is metered down for approximately the next 15 revolutions. This reduced fuel injection rate is necessary for proper warm-up regulation.

3) As the engine speed increases, the quantity of fuel injected is further reduced to a single injection per revolution at approximately 600 rpm.

After starting, warm-up functions are dependent on coolant temperature, engine speed and engine load.