I replaced my drive belt and the old one the tensioner held in the middle of the 3 lines that the arrow points at. Now it's far left. Is the belt too short or is the tensionor not getting the belt tight enough? I tried to measure the new belt and they seem to be the same length. Btw the car has 116k miles and it's never been replaced

 

if you put the old belt back on and its in the middle then the belt isn't the same length