the engine not moving is good IMO b/c there is less chance for the knock sensor to be set off but other things i.e. downpipe hiting frame or headers or heater box, broken motor mount, etc. not sure what kind of strap you use but w/my ratcheting strap there are 2 things you got to pull on to get it to loosen. one of them you go to ratchet it half way and pull on the thing to get it to un-ratchet. sorta hard to explain and i dont remember how to do it w/o looking at it. just study it for a while and you should figure it out.