You flooded your engine.
Good job.
Why did you think it was a good idea to wash your engine compartment?
More than likely, you got water in the electrical, or somehow into your valves. Or sucked into the intake manifold....or pistons....etc....
The fact that it was running, is even funnier. All you did was help it suck water into the engine.
Costs about $1000 to fix, depending on level of damage. Take it to a mechanic, and have them go through it.