I just pulled the new upper chain tensioner I put on a few weeks ago and was extremely surprised to find it still in the "unfired" or "installed" position. Upon inspection and pull apart it seemed reluctant to "fire" on the bench. I cleaned it up and reinstalled, hopefully this time it will expand properly. Has anyone ever heard of this happening? Not exactly the best design I've ever seen.

 

You can normally manually "fire the the tensioner", when it is position, by gentley levering it away from the chain with a large flat bladed screw driver, with the cam cover removed. I wouldn't rely on it being released by normal opperation because the chain doesn't apply enough load on the tesnioner to compress it to release the ratchet inside.