I am brand new to BMW's and I just bought a 1985 528e. I was doing some work on it today and disconnected the battery. After reconnecting it, I started it and made it about 100 feet before dying. It sounds turns over and sounds like it wants to start (fires intermittently), but won't start. I figure it might have to do with the fuel pump or relay, but I was wondering if disconnecting the battery could have anything to do with it. Also, how do I enter a code to make my radio work? What if I don't have a code? Thanks