Un moteur diesel fonctionne sous l'eau. Dont acte !
The idea being that Diesels don't require Electrics to keep running - There's no spark plugs / high voltage coils to get wet.
Of course, in a modern diesel it's mostly computer controlled, but by something in the cab, not computer controlling a coilpack in the engine compartment..
High air intake is only part of it..
Give a diesel engine air and a fuel supply and it'll happily run under water, put a petrol engine underwater and those electrics will stop working at some point (sometimes immediately, sometimes they'll be sealed well enough to last a short time..)