I've got a 1994 320e wagon which wouldn't start. I charged the battery, and it started & drove fine for a day. The next day, the battery was dead. I replaced the battery, but the engine still wouldn't start. I suspect a fuel system problem.

There is a continuous faint, high-pitched humming noise that seems to originate from the electronic fuel injection system (HFM). There's also a lower pitched rhythmic kind of ticking/purring sound which seems to come from the same area.

I manually pulled the throttle cable, and both the humming and ticking noises stopped. I'm going to leave the battery connected overnight to see if the battery drains again.

I've checked to see if there were any bare wires touching metal. I found some bare wires, but none touching metal and apparently unrelated to the problem. I'm stumped and would appreciate any ideas/suggestions for pinpointing or solving the problem.