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2019 440i Gran Coupe - Loss of Power & Hissing Sound Under Boost

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Amanda S. · rep 0 · May 22, 4:04 AM · 1 replies · solved · Question

Vehicle: 2019 BMW 440i Gran Coupe

Hello everyone,

I'm reaching out about an issue with my 2019 BMW 440i Gran Coupe (F36 chassis, B58 engine). Recently, I've noticed a significant loss of power, especially when accelerating hard. Along with this, there's a distinct hissing or whooshing sound coming from the engine bay when the turbo tries to spool up.

The car feels sluggish, almost like it's not getting full boost. The check engine light came on yesterday, and I'm pretty sure it's related to this. I've heard about charge pipe failures on these B58 engines. Could this be what I'm experiencing?

Any insights or similar experiences with your 440i or other B58-powered BMWs would be really helpful. What should I be looking for?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:04 AM

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ClearTheCode admin answer:

Your description of a loss of power, a distinct hissing/whooshing sound under acceleration, and a check engine light on your 2019 BMW 440i Gran Coupe strongly points towards a boost leak, with a failing charge pipe being a very common culprit on B58 engines. This is a well-known issue.

Initial Steps & Diagnostics:

  1. Visual Inspection: Carefully inspect the plastic charge pipe that runs from the turbocharger to the intercooler, and then from the intercooler to the throttle body. Look for cracks, especially near the connections or bends. The B58's factory charge pipe is known to be prone to cracking under pressure.
  2. Listen for Air Leaks: With the engine running (and ideally, someone gently revving it while you listen), try to pinpoint the source of the hissing sound. It will be most prominent under light load or when the turbo is trying to build boost.
  3. Check Engine Light (CEL): The CEL indicates a fault code has been stored. Retrieving this code is the most crucial diagnostic step.

Potential Causes:

  • Cracked Charge Pipe: The most common cause. The plastic material can become brittle over time and crack, especially under the high boost pressures of the B58 engine.
  • Loose Boost Hoses/Clamps: Less common, but a hose could have come loose or a clamp failed.
  • Intercooler Leak: The intercooler itself could have a leak, though this is less frequent than a charge pipe failure.
  • Turbocharger Issues: While possible, a boost leak from a charge pipe is far more likely given your symptoms.

Common OBD Codes:

  • P0299: Turbocharger/Supercharger Underboost Condition
  • P0101: Mass Air Flow (MAF) Sensor Performance Problem (can be triggered by unmetered air entering after the MAF due to a boost leak)
  • P0171/P0174: System Too Lean (Bank 1/2) (also can be caused by unmetered air)

When to See a Shop: It is highly recommended to have your 2019 BMW 440i Gran Coupe inspected by a qualified BMW specialist or dealership as soon as possible. While you can drive it, the engine is not operating efficiently, and prolonged driving with a significant boost leak can potentially lead to other issues. A shop can accurately diagnose the leak using a smoke test or by visually inspecting the charge pipe. Replacing the charge pipe with an aftermarket aluminum one is a popular and durable solution.

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