They were a success! 1806:
Francois Isaac de Rivaz (born in Paris, December 19, 1752; Died in Sion, July 30, 1828) was a Swiss inventor, credited with inventing and constructing the first successful internal combustion engine in 1806. The engine was powered by a mixture of hydrogen and oxygen. The hydrogen gas was contained in a balloon and the ignition was an electrical Volta starter. A year later, Francois Isaac de Rivaz built one of the first automobiles – of course, powered by his new engine.
NOTE: Gasoline was not used for internal combustion engines until 1870.
https://fuel-efficient-vehicles.org/energy-news/?page_id=819
Video of a water powered car from 1974 https://www.bitchute.com/video/VTbTVVWbwMuq/
There's not nearly enough hydrogen in water to replace hydrocarbons, just look at how much less energy you get burning Ethanol (a C2 hydrocarbon) vs Gasoline (a mix of C8/C9/C10s). The energy density of H2 gas is pathetic so it needs to be stored as a liquid at very high pressure and low temperature to compare.
Water is the "ashes" of burning hydrogen, so saying there is a car that runs on hydrogen from water is... Well... No. It absolutely doesn't, unless there a hydrogen fusion reactorin there.
The link you linked is actually about a car that would be accurately described as powered by calcium carbide. And here's where you put the energy in:
Stanly wasn't burning Hy or anything else. His patient hid the true mechanism well. Folks still scratching their heads.
I hate to be a party pooper, but that claim is so huge it would be equally plausible to say it runs on magical unicorn farts... He was likely mistaken about where the energy was coming from or deliberately lying for some reason. Possibly to hide the real mechanism?