No more pops, cracks or burbles with PE
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C43
No more pops, cracks or burbles with PE
My 18 C43 w/performance exhaust always had the satisfying pops, cracks and burbles, as well as a nice burp on upshift when in Sport+ mode, however it has now stopped doing that. It is stock with 75k miles and I can tell that the exhaust is opening up and louder but just not as aggressive. It has not been serviced recently so not flashed.
Any thoughts or advice on what to check?
Any thoughts or advice on what to check?
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My 18 C43 w/performance exhaust always had the satisfying pops, cracks and burbles, as well as a nice burp on upshift when in Sport+ mode, however it has now stopped doing that. It is stock with 75k miles and I can tell that the exhaust is opening up and louder but just not as aggressive. It has not been serviced recently so not flashed.
Any thoughts or advice on what to check?
Any thoughts or advice on what to check?
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Thread Starter
Member
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C43
I’m going to pull codes and if nothing conclusive, run the tank down and fill up. If no luck there, I’ll check spark plug condition.
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I saw that post and will be pulling codes to see what I can find. Currently no CEL but I did have brief loss of Blind Side Assist and Active Brake Assist after using the underspray option at a local car wash. They’ve come back but there may be some correlation there. I do seem to have full power so not sure about limp mode.
I’m going to pull codes and if nothing conclusive, run the tank down and fill up. If no luck there, I’ll check spark plug condition.
I’m going to pull codes and if nothing conclusive, run the tank down and fill up. If no luck there, I’ll check spark plug condition.
Joined: Nov 2016
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Interesting that they go away without some intentional change.
When I first got a Stage 2 tune, I would have those, but drivability was not good. My tuner tweaked settings to improve drivability, but the crackles and pops diminished along with some performance. I did some research as to what causes crackles and pops and discovered they are not really good for your engine, turbo, and/or cats since crackles and pops are the result of excess unburnt fuel exploding in your exhaust system. Not sure what Mercedes does to protect against damage. (On a side-note, I was able to run the Stage 2 original file with no drivability issues once I disconnected my oil pump solenoid.)
You should search "what causes exhaust crackles and pops" and see what is said.
When I first got a Stage 2 tune, I would have those, but drivability was not good. My tuner tweaked settings to improve drivability, but the crackles and pops diminished along with some performance. I did some research as to what causes crackles and pops and discovered they are not really good for your engine, turbo, and/or cats since crackles and pops are the result of excess unburnt fuel exploding in your exhaust system. Not sure what Mercedes does to protect against damage. (On a side-note, I was able to run the Stage 2 original file with no drivability issues once I disconnected my oil pump solenoid.)
You should search "what causes exhaust crackles and pops" and see what is said.
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Interesting that they go away without some intentional change.
When I first got a Stage 2 tune, I would have those, but drivability was not good. My tuner tweaked settings to improve drivability, but the crackles and pops diminished along with some performance. I did some research as to what causes crackles and pops and discovered they are not really good for your engine, turbo, and/or cats since crackles and pops are the result of excess unburnt fuel exploding in your exhaust system. Not sure what Mercedes does to protect against damage. (On a side-note, I was able to run the Stage 2 original file with no drivability issues once I disconnected my oil pump solenoid.)
You should search "what causes exhaust crackles and pops" and see what is said.
When I first got a Stage 2 tune, I would have those, but drivability was not good. My tuner tweaked settings to improve drivability, but the crackles and pops diminished along with some performance. I did some research as to what causes crackles and pops and discovered they are not really good for your engine, turbo, and/or cats since crackles and pops are the result of excess unburnt fuel exploding in your exhaust system. Not sure what Mercedes does to protect against damage. (On a side-note, I was able to run the Stage 2 original file with no drivability issues once I disconnected my oil pump solenoid.)
You should search "what causes exhaust crackles and pops" and see what is said.
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
If bangs, pops and crackles are the result of raw fuel being dumped into the exhaust and igniting explosively when contacting hot metal, I don't see how that helps the turbo to spin faster.
In non-turbo cars, the damage may be less because there are not fragile turbine wheels being exposed to small explosions.
Mercedes must do something to minimize the risk of damage to the turbos.
Last edited by JettaRed; Mar 1, 2025 at 10:25 AM.
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I don't know. But if raw fuel is being dumped through the turbine and ignites downstream, I can't see how that is good. There are two devices that control boost: the diverter valve and the wastegate. The wastegate redirects exhaust gases around the turbine to limit boost, and the diverter valve (DV) dumps boosted air back into the intake after the MAF/MAP and not into the cylinders during off-throttle conditions. A diverter valve releases excess pressure from the turbocharger and directs it back into the intake system. This prevents compressor surge and keeps the turbocharger's compressor wheel moving. (Some people like to replace the DV with a Blow Off Valve (BOV) which dumps boosted (an metered) air to the atmosphere.) BOVs mess up the metering of air causing overly rich conditions. While they may sound cool, they are not helping the engine perform better. DVs are intended to reduce stress on the compressor side of the turbo.
If bangs, pops and crackles are the result of raw fuel being dumped into the exhaust and igniting explosively when contacting hot metal, I don't see how that helps the turbo to spin faster.
In non-turbo cars, the damage may be less because there are not fragile turbine wheels being exposed to small explosions.
Mercedes must do something to minimize the risk of damage to the turbos.
If bangs, pops and crackles are the result of raw fuel being dumped into the exhaust and igniting explosively when contacting hot metal, I don't see how that helps the turbo to spin faster.
In non-turbo cars, the damage may be less because there are not fragile turbine wheels being exposed to small explosions.
Mercedes must do something to minimize the risk of damage to the turbos.
Joined: Nov 2016
Posts: 7,847
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Ya it can't be good, forum member superswiss explains it way better than I ever could: https://mbworld.org/forums/c450-c43-...ml#post8756905
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I'm not sure I understand (and perhaps I should ask @superswiss ), but is he saying that these mini-explosions are a result of adjusted timing of the exhaust cam/valves? If so, where are the explosions occurring? Before the turbo? I'd like to read the technical documentation that describes what is happening. I know they sound cool, but they still seem destructive.
Joined: Nov 2016
Posts: 7,847
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Very good questions to ask about, I am curious as well. Perhaps you could try replying directly in that thread with the questions, he might not see this thread. In case he has auto subscribe set to on in the other thread and will be notified with replies as long as he replies to a new thread, and assuming he didn't unsubscribe.
nice now lets wait for his detailed explanation should help clear things up for us both.
Joined: Nov 2016
Posts: 7,847
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Certainly an interesting approach. I had a Boost Machine device (I don't think they are around any more) that helped hold boost a little longer for quick shifts without slowing down the turbo. It was a device that kinda buffered the boost so that the turbo would maintain speed without suffering back pressure that would slow it down. However, this device did nothing to create pops and crackles.
(Boost Machine was a product by a small company called ModShack. My last contact was in 2016.)
(Boost Machine was a product by a small company called ModShack. My last contact was in 2016.)
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Certainly an interesting approach. I had a Boost Machine device (I don't think they are around any more) that helped hold boost a little longer for quick shifts without slowing down the turbo. It was a device that kinda buffered the boost so that the turbo would maintain speed without suffering back pressure that would slow it down. However, this device did nothing to create pops and crackles.
(Boost Machine was a product by a small company called ModShack. My last contact was in 2016.)
(Boost Machine was a product by a small company called ModShack. My last contact was in 2016.)
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From: Finland
Small leak in the engine breather pipe will effectively stop the pops and bangs.
My car had that happen not that long ago.
it took some time for the leak to get large enough to get a code and soft limpmode.
My car had that happen not that long ago.
it took some time for the leak to get large enough to get a code and soft limpmode.
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Eventually code for air leak, unfortunately I cant remember the code.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
MBWorld God!
Joined: Dec 2019
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Eventually code for air leak, unfortunately I cant remember the code.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
MBWorld God!
Joined: Dec 2019
Posts: 32,222
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Thread Starter
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C43
Eventually code for air leak, unfortunately I cant remember the code.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
but it was like that for almost a month before tripping the code.
its the breather pipe after the throttle body on the intake.
Goes under the manifold.
Very easy to diagnose, just spray brake cleaner under the manifold, if idle stumbles its broken.
Junior Member
Joined: Oct 2024
Posts: 52
Likes: 8
From: Finland
Thread Starter
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Posts: 143
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C43
Had the car checked at dealer and no codes. I’ve replaced spark plugs and am running fuel injection cleaner through. I do now believe that the PE isn’t opening all the way or at all, because sound is not really louder except under full throttle. I know the module that opens the valves could go bad but is there also a fuse that I can check? Any other ways to determine if the valves are opening at all?
Found this post, which is my next thing to look at:
https://mbworld.org/forums/c450-c43-amg/681686-c43-performance-exhaust-valve-stopped-working.html
Found this post, which is my next thing to look at:
https://mbworld.org/forums/c450-c43-amg/681686-c43-performance-exhaust-valve-stopped-working.html
Last edited by Shotime; Mar 18, 2025 at 05:10 PM.
