745 starting problem, earthing faults ?

Hello !

Anybody having experienced of a problems to start your 745, at
temperature levels of about +1 to +8 Celsius (I have a 1988 model). Not
any problem at colder temperature. In the temperature range of about +1
to +8 Celsius it looks like the engine does not ignite anything, or very
sporadic, but if engine starts it comes white and black smoke from
exhaust. (too much fuel?) If it does not start, I can wait 15 minutes,
and then the engine starts almost without any problem.

I have no problem with the battery, enough power seems to be available.

My guess is that I have some kind of earthing problem somewhere giving
too little power to electronic ignition parts. Anybody that have similar
experience, or have information about earthing in the car, or where is
the electronic ignition 'box' located ? hints ?

Regards Bjorn