OP stated that he's replaced the fuel pump and filter, then jumpered the fuel pump relay to confirm that fuel was being injected.

If water did get sucked up through the fuel system and sat for a period of time, it's possible that the injectors are seized and not "popping". Likewise if the fuel filter ruptured and let some crap through the lines, the little screens in the injectors could be clogged shut.

OP: Have you tried dumping a cap of fuel down the air inlet to see if the car will catch on fuel vapor? That would help rule out ignition issues.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]