Don't crank the engine when the plugs are out unless you disable the ignition. A stray spark will light off the raw fuel floating around.

A vacuum referenced fuel pressure regulator will have 3 lines, two that are about 5/16 diameter are fuel and one in the 3/16" range is engine vacuum that should be dry.

You will need to pull the plugs and clean / dry them. Also let the engine dry out.