NO WAY!
Making a carburator that will disperse water into a manifold system is not too tough.
Making the water explode in the cylinder is a little tougher!
I know it sounds Stupid!, but it is easy to explain.
Old style "steam engines" used an external combustion heat source to produce steam for engines which were not much different in function than locomotive engines.
Modern automobiles use internal combustion engines to capture the mechanical energy of expanding gases, while throwing away the heat energy, (think of all the heat that is discarded by the radiator!)
What I propose is a means of combining these techniques to gain the mechanical energy as well as the heat energy of the engine. If combined with other efficiencies, such as regenerative braking systems, one could envision a very efficient automobile indeed.
Sure, it sounds stupid, but why not?