There's no diaphram in the lift pump, it's a piston. If you remove the 30mm (maybe 32?) nut on the front of pump you will see the spring and piston behind it. If you are going to take it apart be careful because that spring is under some pressure. I seriously doubt you broke the lift pump by spraying stuff in your cylinders and that there is probably no reason to take it apart.

Try putting it all back together and pump the primer until you hear the relief valve operating and fuel is flowing through the return line. If your system has an empty secondary filter or lines full of air this may be 50 or more strokes on the primer. Then crack all the injector lines and crank the engine until you see fuel coming out the lines. Air in the injection system can make it seem like the whole thing just died but just takes some purging.