BMW i3 Air Intake Problems, Symptoms and Troubleshooting

Hey there! I have some experience working on hybrids, and I dealt with something very similar on my 2015 BMW i8 (also had an i4 before). Had those exact symptoms, hissing, poor performance, and that annoying check engine light. Turned out my intake hose was cracked and leaking. Got it fixed at my regular workshop, cost me around 100 bucks and solved all those issues you're describing. Mind sharing your mileage and whether you've noticed any specific conditions when the symptoms get worse (like cold starts or during acceleration)? This info could help confirm if we're dealing with the same problem. Quick tip: Before heading to the mechanic, check if you can hear the hissing sound getting louder when you rev the engine slightly while parked. This helped my mechanic pinpoint the issue faster.

Thanks for the detailed response! My i3 just hit 171716 KM and had its last service about 2 months ago. The hissing is definitely more noticeable during acceleration, especially when I give it more throttle. I haven't really paid attention to cold starts, but now that you mention it, the engine does seem more jumpy in the morning. Your experience with the cracked intake hose sounds very similar to what I'm dealing with. Did you notice any specific location of the leak? I tried looking around the engine bay but there's so many hoses, I'm not sure where to focus. That 100 bucks repair sounds way better than what I was fearing it might cost!

Hey again! Glad to hear back from you. Yeah, from what you're describing, it sounds exactly like what I dealt with on my i8. When you mentioned the morning jumpiness, that's a dead giveaway, cold air makes these leaks more noticeable. In my case, the crack was actually pretty tricky to spot at first. It was in the rubber hose connecting to the throttle body, right after the air filter housing. Had a hairline crack that you could barely see unless you were really looking for it. The mechanic actually used some soapy water to find it, the leak made bubbles when the engine was running. With that mileage on your i3, it's pretty common for these rubber parts to start showing their age. Mine was around the same mileage when it happened. The good news is that these hoses are usually pretty straightforward to replace. Quick thing though, while you're at it, might be worth having them check the other rubber hoses nearby. My mechanic showed me that when one starts going, the others aren't far behind. I ended up replacing a couple of nearby hoses preventively, and I'm glad I did. Still worked out cheaper than having to go back multiple times.

Thanks, that's super helpful! I'll definitely get them to check all the rubber hoses while they're at it, makes total sense to do it all at once rather than making multiple trips. The soapy water trick sounds clever, I might try that myself before heading to the shop just to get an idea of what I'm dealing with. Really appreciate you sharing your experience, it's given me a much better idea of what to expect. I was worried it might be something major, but this sounds way more manageable than I feared. I'll get it booked in this week and make sure to mention the throttle body connection area specifically. Thanks again for taking the time to help out!