Got banned from a car forum for saying don't wash your engine bay with a garden hose, and I learned that lesson the hard way in Toledo | Banned But True - Free To Speak
Went through the same thing with my old truck and what saved me was covering the alternator and fuse box with plastic bags before spraying anything. Use low pressure only and stay away from the intake, then let it air dry or hit it with a leaf blower. Works fine every time as long as you prep it right.