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So, was the plastic deformed preventing the clamp on the Y pipe from creating a seal? That gap where you put the silicone is inside the Y pipe so I'm not picturing what you fixed.
EDIT: Wait... was air actually flowing between the metal and plastic on the INSIDE undetected by the sensor?
I'm not sure if the plastic deformed so much, but the fit certainly wasn't sealed/leak-free. But yeah, air was flowing undetected by the MAF.
Originally Posted by roadkillrob
Thanks, will certainly check this out ASAP!
Keep us posted
Originally Posted by skratch77
Can we just take the metal out?
Sadly not...the black plastic velocity stack would have nothing to clip onto and besides, the airflow would end up being too turbulent through the MAF (due to the super short oval pipe) and as a result, the car will not like it at all when you go anywhere at WOT. Don't ask me how I know
I'm not sure if the plastic deformed so much, but the fit certainly wasn't sealed/leak-free. But yeah, air was flowing undetected by the MAF.
Keep us posted
Sadly not...the black plastic velocity stack would have nothing to clip onto and besides, the airflow would end up being too turbulent through the MAF (due to the super short oval pipe) and as a result, the car will not like it at all when you go anywhere at WOT. Don't ask me how I know
sorry i still cant picture what you are saying. Shouldnt there be two clips each on one side to secure the intake filter cover to the oval velocity tube?
Rudimentary 'chop to highlight the 'shiny' bits which is where the glue/epoxy was used to fill the gaps. The red lines are approximately where the shiny bits are, but i didn't want to draw over them of course.
Originally Posted by Rick X Joaquim
sorry i still cant picture what you are saying. Shouldnt there be two clips each on one side to secure the intake filter cover to the oval velocity tube?
Yes indeed. The leak is 'internal' to the engine. Although the black rubber thingy is sealing the airbox oval tube from outside air, the air in question here is seeping in-between the aluminium tube and the plastic airbox shell. It should be going past the MAF....but a small (tiny) amount of air isn't doing that. Once sealed up, all air will ingest via the MAF and the PCM will then be able to correctly make allowances in terms of fuelling.
Rudimentary 'chop to highlight the 'shiny' bits which is where the glue/epoxy was used to fill the gaps. The red lines are approximately where the shiny bits are, but i didn't want to draw over them of course.
Yes indeed. The leak is 'internal' to the engine. Although the black rubber thingy is sealing the airbox oval tube from outside air, the air in question here is seeping in-between the aluminium tube and the plastic airbox shell. It should be going past the MAF....but a small (tiny) amount of air isn't doing that. Once sealed up, all air will ingest via the MAF and the PCM will then be able to correctly make allowances in terms of fuelling.
If the air is leaking at junction of aluminum and plastic tube, it already passed thru the maf sensors. I can only think in this case the engine is recieving less air as what the maf reads
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Rick X Joaquim
If the air is leaking at junction of aluminum and plastic tube, it already passed thru the maf sensors. I can only think in this case the engine is recieving less air as what the maf reads
No, the air comes from the other side dude. It’s going up above and past the MAF and into the engine where he’s showing that he filled in with silicone.
Edit: I didn't realize that ROW boxes also have the steel sleeve, and I have them. I guess let's try sealing first.
But this would be strange if it works. Because most people have new ROW boxes, to where if this an issue that comes up say at 60K miles due to expansion and contraction and then the gap widening, almost nobody here would have it.
MY ROW have 1000 Miles or so.
If the design was defective, ALL M156 would have it and Mercedes would have TSB-ed it and there would be a substituted part number. Or maybe all ROW cars run the 25% LTFT? And why are the US boxes exempt from the same sleeve issue?
Here's a closeup from some ROW diy thread. I would think it would be better to seal it on the leading edge though rather than where Celicasaur sealed his.
Here's a closeup from some ROW diy thread. I would think it would be better to seal it on the leading edge though rather than where Celicasaur sealed his.
I considered the inside, but getting an easy/clean job would have been tricky with accessibility via a gloopy blob of epoxy on a swap stick, so i carefully did the rear. But yes, the inside would be better in theory definitely. In practice, probably not any real-world difference. A good seal either way is the important thing.
I considered the inside, but getting an easy/clean job would have been tricky with accessibility via a gloopy blob of epoxy on a swap stick, so i carefully did the rear. But yes, the inside would be better in theory definitely. In practice, probably not any real-world difference. A good seal either way is the important thing.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Originally Posted by Rick X Joaquim
By the way, did the original poster fix the problem? Withthis?
I have not, I am going to work on it tomorrow and check to see if there is a gap in mine - bought them new, maybe 2000 miles on them, trims are perfect with oem boxes, high 20's with rows at idle, switched them back and forth a few times and problem only exists with Rows after several changes back and forth.
So I asked myself, how come Mercedes didn't think of this and BTW, what retains the steel sleeves inside the plastic housings.
I am beginning to have a theory:
Mercedes DID think of this, but they used a cheap resin. Look at the yellow residue. It dries in time and transforms into a powder and loses sealing properties. It became so brittle that I could just pull the metal sleeve out with needle nose pliers, without much effort at all.
What I don't understand is if the M156 can really collapse the MAF sections under full load. It may be possible.
The Subaru can collapse a 4 ply silicone hose, basically more than 1/4" thick.
I very much agree with sealing the leading edge, but look how irregular it is and one cut out is deeper than the MAF cutout itself. also and this is not clear in the posted pictures, the steel sleeve has an instance where it overlaps the black plastic framework. So it doesn't only go inside the silver piece but one leading edge goes over a seam between the silver and black pieces, very sketchy.
I think that a bead of high temperature silicone may take care of this, if there is anything to it.
So I asked myself, how come Mercedes didn't think of this and BTW, what retains the steel sleeves inside the plastic housings.
I am beginning to have a theory:
Mercedes DID think of this, but they used a cheap resin. Look at the yellow residue. It dries in time and transforms into a powder and loses sealing properties. It became so brittle that I could just pull the metal sleeve out with needle nose pliers, without much effort at all.
What I don't understand is if the M156 can really collapse the MAF sections under full load. It may be possible.
The Subaru can collapse a 4 ply silicone hose, basically more than 1/4" thick.
I very much agree with sealing the leading edge, but look how irregular it is and one cut out is deeper than the MAF cutout itself. also and this is not clear in the posted pictures, the steel sleeve has an instance where it overlaps the black plastic framework. So it doesn't only go inside the silver piece but one leading edge goes over a seam between the silver and black pieces, very sketchy.
I think that a bead of high temperature silicone may take care of this, if there is anything to it.
interesting theory
they don't collapse at wot through 2nd,3rd and 4th or they didn't on the multi runs I made
also my car felt slightly better with the tube removed
in fact I can't remember if mine are still out or not
I very much agree with sealing the leading edge, but look how irregular it is and one cut out is deeper than the MAF cutout itself. also and this is not clear in the posted pictures, the steel sleeve has an instance where it overlaps the black plastic framework. So it doesn't only go inside the silver piece but one leading edge goes over a seam between the silver and black pieces, very sketchy.
I think that a bead of high temperature silicone may take care of this, if there is anything to it.
JB Weld epoxy putty. Then you can sand it down smooth once it has cured.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Ok, I removed the row airboxes again and went back to stock. I can see a little light past the metal sleeves, but it is not much, doesn't seem enough to make a difference like I am seeing, but I can't find any other explanation, so going to warm them up, seal them up and try them again.
Understanding a closed loop system, the O2's see things too lean, so request more fuel, so only explanation is that the MAF's are not seeing the air and not requesting enough fuel and if that is the case and the only change is the airbox lid, it has to be something with the lid not measuring the airflow properly.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Jasonoff
JB Weld epoxy putty. Then you can sand it down smooth once it has cured.
Nah, just use silicone. It’s safer and will accomplish exactly the same thing. I also thought about using JBWeld on my TBs, but I’d rather not put something inside my intake that might damage the engine if a piece breaks loose somehow and gets sucked in (however unlikely that may be).
I think silicone is safer too.
I don't think it's possible to remove the steel sleeve without recalibration/scaling of the maf table.
The tube in which the maf sits should be considered of a calculated cross section and in order to change this section by removing the steel sleeve, you need to have access to the table to adjust/scale it.
Ok, I removed the row airboxes again and went back to stock. I can see a little light past the metal sleeves, but it is not much, doesn't seem enough to make a difference like I am seeing, but I can't find any other explanation, so going to warm them up, seal them up and try them again.
Understanding a closed loop system, the O2's see things too lean, so request more fuel, so only explanation is that the MAF's are not seeing the air and not requesting enough fuel and if that is the case and the only change is the airbox lid, it has to be something with the lid not measuring the airflow properly.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Originally Posted by Rick X Joaquim
did u see any gap with the stock cover?
I can see just the slightest bit of light through one of them and the other one just a tiny bit where the steel tube is crimped - doesn't seem like enough but I can't see any light through my stock ones at all.
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