G Class (W465/W463A) W463 Produced 2019-2024: G550, G63 AMG W465 Produced 2025-

Exhaust valve always open mod - CEL

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Old Apr 24, 2023 | 10:32 PM
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G550
Exhaust valve always open mod - CEL

Hi, I wanted to see what the G550 would sound like with the valves always open and found that under the valve motor is a spring that comes right off - this spring connects the valve motor to the exhaust valve/flapper. I simply removed the spring, safety wired the valve open and put everything back. Didn't even disconnect the valve motor. Has anyone else tried this? I did one side and started the car - it was fine. Did the other side and now the CEL has popped up and I believe the car is in limp mode. No info on the dash aside from the CEL. Pulling the codes tomorrow.
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Old Apr 25, 2023 | 09:47 AM
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Originally Posted by myfirstg
Hi, I wanted to see what the G550 would sound like with the valves always open and found that under the valve motor is a spring that comes right off - this spring connects the valve motor to the exhaust valve/flapper. I simply removed the spring, safety wired the valve open and put everything back. Didn't even disconnect the valve motor. Has anyone else tried this? I did one side and started the car - it was fine. Did the other side and now the CEL has popped up and I believe the car is in limp mode. No info on the dash aside from the CEL. Pulling the codes tomorrow.
Probably triggered the Catalytic converters low back pressure sensor. That valve is only supposed to open under higher exhaust pressure to maintain efficacy of the catalytic converter and engine efficiency.

Last edited by haa; Apr 25, 2023 at 09:50 AM.
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Old Apr 27, 2023 | 07:30 PM
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Porsche gt3 trading to amg gtr
I have the Renntech evm for 3 years now. I always keep the exhaust loud and never had a cel. I installed myself. Easy 30-40 min job.
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Old Apr 27, 2023 | 07:56 PM
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I am pretty positive the CEL is due to the flapper motor is not having anything to rotate - it can't find the end stops. Since I don't ever plan on closing the flaps, I'm going to make these caps with end stops inside so I can leave the flaps safety wired open.

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Old Apr 28, 2023 | 05:44 PM
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Originally Posted by V8ray
I have the Renntech evm for 3 years now. I always keep the exhaust loud and never had a cel. I installed myself. Easy 30-40 min job.
curious about the Renntech product?
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