That is odd... just swapping the crank pulley shouldn't cause your problem.... unless maybe the pulley is slipping on the crank???

1. did you get the new pulley seated all the way?
2. did you use a new bolt?
3. did you get the bolt tightened to spec?

That is all I can think of that could go wrong with the swap....(other than damaging the front seal)...

Keep us posted....