Dropped my iPhone 4 in pee? What's wrong with it?

Ok so I'm going to list all the details I have, state my thought process on a solution, and try to get a iPhone expert to get me pointed in the right direction so I can fix my iPhone 4. A while back I dropped my iPhone 4 in the toilet, so no this wasn't recent, i did the rice trick and all that stuff, removed the SIM card, and managed to salvage some of the iPhone. The iPhone only turns on when plugged into the wall, doesn't work when plugged into the computer (iTunes doesn't pick it up either). When the phone turns on it requires me go plug it into iTunes and reactivate it (there's no SIM card in it). Also, when the phone turns on it says the battery is full charged (100%), so that makes me think that it's not the dock connector and the battery itself is being charged. Therefore I have come to the idea that the battery has software issues and can't sustain itself and stay on. I ordered the tools and the battery to see if i can try that and maybe fix it, but if that isn't the issue what else could it be? What else should I try? Should I replace the dock connector if the battery doesn't work? This is not urgent because I have been using my old iPhone 3GS, but is more about learning. I want to become a mechanical engineer and I feel like this might be a good project for me. A simple idea as to what might be wrong with the Phone is appreciated.

If you are phone is still in warranty replace it

Be more careful with the replacement.