It's hard to describe, but I'll try.
OK, you already replaced the "cam" part that the rod attaches to right?
That cam part slips onto the tensioner itself onto these 2 "flat spots", directly opposed from eack other. OK, these 2 flat spots should be "aimed" at the center of the idle pulley on the tensioner. If this alignment is off by more than 10 degrees, the tensioner is worn out. I'm betting it's off by alot more than that.