Inconsistent Engine Output
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Joined: Feb 2024
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2015 GL 450 4Matic
Inconsistent Engine Output
Hello there. I am searching for any expertise or thoughts on a few issues. I have a 2015 GL 450 with 114,000 miles. This car has been kept in extremely pristine condition. The has been dealer serviced since the car was purchased brand new. It has had all of the recommend maintenance. The car has the 3.0L twin-turbo V6 engine.
Issue #1: I noticed that there is a significant difference in power output from the engine. Used my Icarsoft code reader to investigate. Upon checking, the code says that turbo charger #1 is not making enough boost pressure. The turbo has never been replaced, but looks fine from the visual inspection i performed. Weirdly, if you shut the engine off and turn it back on, the turbo magically starts working again. This leads me to believe it could be 1 - electrical, 2 - a relay or vent sticking open/closed, or something else that’s going to hurt my pockets lol!
Issue #2: I have noticed a jerky feeling when giving the engine a bit of gas. As the rpms climb it starts lightly jerking. Nothing crazy, but it’s noticeable. It seems to be doing it most noticeably in 4th gear. This issue is occurring both when turbo is working and when not. The jerking also immediately stops when boost pressure hits. I don’t think it’s the transmission and i also doubt it’s the timing chain, but i honestly don’t know.
The issue seem partly related, so I’m just trying to make sense of any possibility.
I would really appreciate any feedback or information that anyone may have.
If anyone needs more information or anything, please leave a comment or PM me.
Thank you!
Issue #1: I noticed that there is a significant difference in power output from the engine. Used my Icarsoft code reader to investigate. Upon checking, the code says that turbo charger #1 is not making enough boost pressure. The turbo has never been replaced, but looks fine from the visual inspection i performed. Weirdly, if you shut the engine off and turn it back on, the turbo magically starts working again. This leads me to believe it could be 1 - electrical, 2 - a relay or vent sticking open/closed, or something else that’s going to hurt my pockets lol!
Issue #2: I have noticed a jerky feeling when giving the engine a bit of gas. As the rpms climb it starts lightly jerking. Nothing crazy, but it’s noticeable. It seems to be doing it most noticeably in 4th gear. This issue is occurring both when turbo is working and when not. The jerking also immediately stops when boost pressure hits. I don’t think it’s the transmission and i also doubt it’s the timing chain, but i honestly don’t know.
The issue seem partly related, so I’m just trying to make sense of any possibility.
I would really appreciate any feedback or information that anyone may have.
If anyone needs more information or anything, please leave a comment or PM me.
Thank you!
Super Member
Joined: Jul 2019
Posts: 733
Likes: 297
From: New Orleans
2014 GL450, 1992 W140 300SD, 1993 W140 300SE, 1987 E30 Convertible
Low boost. check turbo actuators, vacuum lines, turbo control vacuum electromagnet and line going to vacuum pump. There is a check valve in vacuum pump for turbo vacuum outlet, then it dies your vacuum lines start taking oil.
