Time control in computer chess

I hadn't made any major attempts at improving my chess engine. I had just added some features to the evaluation routine. So, I thought why not add time control to it ,so that it doesn't always do a fixed depth (4 ply) search. I looked up some texts and came up with a way to do an iterative alpha beta search with time control. I was able to implement it, but the results were bad. The chess engine started playing badly. So I reverted back to the older fixed depth search. (Sigh..)