lenashadow1

AMG GT Turbo Issues and Resolution

My 2017 Mercedes AMG GT with a gasoline engine is acting up. The check engine light's on, and it feels like half the horses went on vacation. I'm getting poor engine response, a weird whistling sound, and a loud hissing sound when I accelerate. It even stalled at idle the other day and fuel consumption is definitely up. I'm guessing it has something to do with the turbocharger because it's making those whistling noises, but the mileage is already at 298749 km. Has anyone else experienced something like this? Could it be the boost pressure actuator? My gut is telling me it's the electrical bypass valve, but I don't have the tools to properly diagnose. Any advice?

4 comment(s)

Sounds familiar. I've had similar issues with my AMG GT. Whistling and hissing is almost always a boost leak in the turbo system. If the actuator valve for the boost pressure is faulty, the turbocharger won't be able to regulate the boost correctly, leading to power loss and those strange noises. The stalling and increased fuel consumption also point towards that direction. Have you checked for any obvious cracks or loose connections in the hoses related to the turbo system?

Thanks for the quick response! So, 'boost leak' makes sense. What exactly is the actuator valve doing? And where exactly should I be looking for these cracks and connections? I'm not super familiar with the turbo system layout on this car.

The actuator valve controls how much boost the turbo system produces. Think of it as a gatekeeper for the pressure. If it's not working correctly, it can either overboost (rare in your case since you're losing power) or underboost, which sounds like what's happening. A defective electrical bypass valve can cause the valve to not open or close properly. Honestly, without proper tools, it's tough to pinpoint the exact location of the boost leak. Given all the symptoms, I'd suggest taking it to a trusted workshop. They can pressure test the system and accurately diagnose the issue.

I took it to a local shop. They confirmed it was indeed the boost pressure actuator valve. Seems like the electrical bypass valve was defective, just like I suspected. Replaced it, and the whistling, hissing, and power loss are all gone! Runs like new. Total repair cost was around 250€. Thanks for pointing me in the right direction!

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