BMW Z3 Cold Start Issues: Injector or Something More?

Hey there! I had almost identical issues with my 2004 BMW Z4 last winter. The symptoms were spot-on with what you're describing, hard starts, excessive fuel consumption, and rough idle until warm-up. Initially, I also thought it was just the cold start injector. Took it to my mechanic, and diagnostic tests revealed two faulty fuel injectors that were causing uneven fuel distribution. It was actually a serious issue that needed immediate attention because bad injectors can damage your catalytic converter and engine over time. The fix involved replacing both defective injectors and cleaning the remaining ones. Got it done and the difference was night and day, starts perfectly now, even in cold weather, and the rough idle is completely gone. Fuel economy went back to normal too. If your symptoms match mine, I'd strongly suggest getting it checked out sooner rather than later. These injection issues usually don't fix themselves and tend to get worse over time. The repair wasn't fun, but it was absolutely necessary to prevent bigger problems down the road. Best of luck with yours!

Thanks so much for sharing your experience! Great to hear you got it sorted out. Quick question, do you remember roughly how much you ended up paying for the injector replacement and cleaning? Also, has everything been running smoothly since the repair, or have you noticed any other quirks pop up? Your insight would really help me budget for this repair.

Hey again! Happy to follow up! Since you asked, I got mine fixed about 3 months ago and it cost me 515 € for replacing that faulty cold start injector. Money well spent if you ask me! The mechanic confirmed it was exactly what I suspected, a defective injection valve causing all those annoying cold start issues. The best part? Everything's been running like a dream since then. No more of that frustrating rough idle in the morning, and my fuel consumption is back to normal. The car starts up perfectly now, even on those chilly mornings. Seriously, it's like having a different car! Trust me, getting it fixed was totally worth every penny. It's such a relief not having to worry about whether the car will start properly anymore. Plus, I'm probably saving money in the long run since I'm not wasting extra fuel during warm-up anymore. Let me know if you need any other details about the repair. Always happy to help out a fellow BMW owner!

Thanks for all those details! I actually took your advice and bit the bullet, went to a mechanic last week. Turns out my case was a bit different though. The mechanic found that the main issue was a clogged fuel filter combined with a failing fuel pump. Total bill came to about 650 for parts and labor, which wasn't as bad as I'd feared. The mechanic was really thorough and even showed me the old parts, you could actually see how gunked up that filter was! Been driving for a few days now and what a difference. No more stuttering on cold starts, and the engine purrs like it should. Really glad I asked here first, your experience gave me the push I needed to get it checked out before it turned into something worse. Sometimes you just have to trust the right professional to do their job. Thanks again for helping me avoid what could've been a much bigger headache down the road!