Engine knock after fuel pump exchange

[theirishpope]

I am going to put this out here to get some opinions. Couple of months ago my 01 gold alero 2.4 engine blew the fuel pump, checked through all the options I could think of before determining it was the pump. At the time I could not afford the pump so it sat down in the drive way. I just finished installing a new pump on it and did the first start up and now the engine has a knocking sound. Thoughts?