The computer may not be fried, but it may not be running correctly either. The EMM is sealed, although that doesn't guarantee no water can intrude. Remove the harness connectors and spray clean them both the EMM and the harness with electronic cleaner, available at Wal-mart or any auto parts store. Do it for all the connectors on the engine.
Was this fresh or salt water and how long?
The starter may need going through and most relays and solenoids will eventually need replacing.
Make sure your fuel is free of water and all filters clean.
You can't just switch EMM's. You could just to do a quick comparison, but the EMM's are matched to the injectors. If you want to do a permanent repair you need to replace the injectors from the other engine as well, and don't get them mixed up. Top cylinder, to top cylinder.
If you have to replace the EMM you need to contact your local dealer to do it. You can't just slap it on or engine damage could occur or if nothing else your engine just may not run at full power or unevenly.
So clean all the fuel, filters and connectors and see what it does first. There can be no corrosion or water in any connector.
Are you getting lights on the EMM when cranking and running? Cranking is OK, running no lights.
Let me know how you make out.