Changed fuel injector, car won't start

Hello, Well I noticed the smell of gas in my 1997 cavalier 2.2L. (evidentally this is typical) I noticed that the 4th injector was leaking. I changed the seals, same problem. To make sure it was the injector itself, I swapped it with another. It did leak. So I finally decided to replace it with a new injector. after i installed, the car would not start! I tried putting the old injector in, still did not work. changed all the plugs, checked to see if they spark..they did. As I am trying to crank the engine, fuel is spitting out of the exhaust pipe. it would try to start and barely run like it was on 3 cylinders then die. it seemed like it was flooded badly. DO I need to reset the ECU or something? and if so, where is it located and how do I do it. Does the fuel pump need to be reset? again...where is it? Why didnt this happen any of the other times I took off the injectors? Is there a bad sensor? Everything was plugged in correctly. Please help, no transportation now.
JAY

your missing something on the install, make sure your not missing any connecters, double, tripple, quaruple check everything. resetting the ecu usually happens when the battery or fuse is disconnect for 10-15minutes.