I would most definately NOT use a jar of coins in an effort to deter him... instead of just hiding behind the sofa, he'll start peeing behind it too!
Is he neutered? (sorry can't remember if you mentioned it previously) JMO - I don't believe furbabies should have free-run if they aren't potty trained. I would return to confinement and positive reinforcement training.
There are others more experienced with potty training here, and there are many detailed threads on potty training you can search on this forum; but you will find that none of them recommend negative reinforcement
I wish you the best of luck.