Actually, it is pretty normal. Water made during the burning of fuel condenses in cold exhaust. In old richer running vehicles there is often some soot formed in the richer regions of running, cold start is one of those regions. The soot mixes with the water and makes a mess.

Obviously, if your car ran leaner less soot would be available to mix with the water. If you get that guy lean enough to get 17mph on the road you will have much less soot.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician