Z4 Starting Nightmares: Bad Switch or Something More?

Hey there! I had nearly identical issues with my 2006 BMW Z3 last year. The symptoms you're describing match what I experienced, intermittent starting problems and rough running when it did start. Initially thought it was the ignition switch too, but when I took it to the garage, they diagnosed a blown fuse and faulty fuel pump relay. The mechanic showed me that the old fuse was completely burnt out, which was causing the electrical system to act up. They replaced both parts, and the car's been running perfectly since. While the fuse itself wasn't a major repair, the failing relay could have led to bigger problems if left unchecked. The fuel pump could have been damaged, which would've been much more serious. I'd recommend getting it checked soon, these symptoms usually don't fix themselves and might get worse. Best to have a professional look at the electrical system to pinpoint the exact issue. Make sure they specifically check the fuses and relay system before replacing the entire ignition switch. Could save you from an unnecessary repair.

Thanks for sharing your experience! That's really helpful information about the fuse and relay system. Glad you got it sorted out. Do you remember roughly how much you ended up paying for the repair? Also, have you had any other electrical issues pop up since then? Just want to know what to expect if it turns out to be the same problem with my Z4.

Hey again! Happy to give you an update. The repair was actually pretty reasonable, I paid 52€ for the fuse replacement. And you'll be glad to know I haven't had a single electrical issue since getting it fixed. The car's running as smooth as butter! Looking back, I was also convinced it was the ignition switch (just like you), but taking it to the mechanic was definitely the right call. They spotted that burnt-out fuse right away, and once they replaced it, all those annoying symptoms, the rough running, unusual dying, and starting problems, completely disappeared. My advice was spot on about checking the fuses first. Saved me from spending way more on an unnecessary ignition switch replacement. Been driving my Z3 for over a year now without any problems. These BMWs are solid cars, they just need the right diagnosis. Hope you get yours sorted soon, sounds exactly like what I went through!

Thanks for all the info! Finally got my Z4 checked out yesterday. Turns out my issue was a bit different, had a faulty crankshaft sensor that was causing all the trouble. Cost me more than your repair, around 175 for parts and labor, but honestly, I'm just relieved it's fixed now. The mechanic I found was great, really took the time to explain everything and even showed me the old sensor. Car's running like a dream now! Much better than my previous mechanic who just wanted to replace everything without proper diagnosis. Funny how we both thought it was the ignition switch at first. Goes to show it's worth getting a professional opinion instead of trying to diagnose these things ourselves. Really appreciate your help in pushing me to get it checked out properly. Now I can finally enjoy driving my Z4 again without worrying about it dying on me!