You've swallowed a gut full of water, (remember that it's a 22.7:1 compression engine, a single teaspoon of water can ruin everything) lost compression on 1 cylinder and the first thing the mechanic wants to do is replace all the fuel system.



When you cranked it over did any water come out?

Unless there is some crucial info you've left out as to why an injector pump/injector replacement is going to restore compression given the current info , I think you need to find another mechanic.