This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
From: (e-mail address removed) (Mo Brooks)
Smoke Color / Reason
Black = Too much fuel (probably bad sensor or dirty air cleaner)
Blue = Oil
White = Water
Black smoke on acceleration in early 2.2l engines may come from the fuel
pressure regulator vacuum hose at the elbow; may be a bad injector; or may
be duel to high fuel pressure. You may want to check for restrictions in
the fuel return line.