I read in an interview with Michael Pare' that the script for Eddie and the Cruisers 2 included details as to what happended after he drove off the bridge but for some reason wasn't included in the movie.
After driving off the bridge, he ended up swimming to shore and staying at a motel nearby. He turned on the television and saw on the local news that he was presumed dead. Feeling like he had to reason to stay now, he decided to drop out of society. He went and got his seaman's papers, lived a life on a ship at sea for many years until he decided to come back. He couldn't go back to Jersey, so of course, Canada was the closest he'd come.