Smell of sulfur but no performance drop
05-08-2020, 07:54 AM
#1
Junior Member
Thread Starter
Smell of sulfur but no performance drop
Hi
07 clk550 coupe here.
I have a high pitch noise from my car, coming from under. It sounds like those cutes pipes outside people doors in the wind doing soft metal musical sounds chiming...huh... I'm lost...oh, yeah, so musical high pitch sounds at low speed. I also have a smell at random times, of rotten eggs out coming off of the exhaust, at times even in the cabin. I couldn't identify the noise source (heat shield, brakes etc).
No engine lights, scanner codes, or abnormal behavior. The car runs great and is really responsive when accelerating ! I'm tempted to say almost better that usual. Noise comes out after a ride long enough to get everything warmed up.
My good friend R , king of the CLK, told me to look at this and that but I couldn't find much linked to the noise so far since it's not consistent and I can't always reproduce it anyways. The smell says catalytic converter but would that not affect the performance ? Btw I use shell techron and VTech 91 gas. Could they smell? Wishful thinking....
Should I try changing the O2 sensors first? How easy are they to fix? I could replace the whole exhaust system but it's super expensive so...
Anything else I should look at?
Thanks
07 clk550 coupe here.
I have a high pitch noise from my car, coming from under. It sounds like those cutes pipes outside people doors in the wind doing soft metal musical sounds chiming...huh... I'm lost...oh, yeah, so musical high pitch sounds at low speed. I also have a smell at random times, of rotten eggs out coming off of the exhaust, at times even in the cabin. I couldn't identify the noise source (heat shield, brakes etc).
No engine lights, scanner codes, or abnormal behavior. The car runs great and is really responsive when accelerating ! I'm tempted to say almost better that usual. Noise comes out after a ride long enough to get everything warmed up.
My good friend R , king of the CLK, told me to look at this and that but I couldn't find much linked to the noise so far since it's not consistent and I can't always reproduce it anyways. The smell says catalytic converter but would that not affect the performance ? Btw I use shell techron and VTech 91 gas. Could they smell? Wishful thinking....
Should I try changing the O2 sensors first? How easy are they to fix? I could replace the whole exhaust system but it's super expensive so...
Anything else I should look at?
Thanks
05-08-2020, 05:43 PM
#2
MBWorld Fanatic!
I would suspect the cats; because of the smell and the clinking sound. It may be that the primary cat has partially gutted itself with pieces of its core bouncing around at the input to the secondary cats. The performance may improve because of the initial increased air flow due to the deteriorating primary cat/s. As the debris collects at the input to the secondary cats performance will deteriorate.
If you have removed the secondary cats, the debris from the primary cats will find its way to the exhaust exit. In this case you will start to see pieces of gray or whitish pieces of thin metal or ceramic material at you exhaust exit. If you rev the engine a few times, you may see particles on the surface behind the car; much more and larger if the secondary cats have been removed. I believe the OE muffler is a straight through design and will not stop debris unless it is a fairly large chunk.
Since you can occasionally hear what I think you're saying is a light rattle, I would guess your secondary cats are still in place. If you do quick revs, to about 1200-1400 RPM then quickly let off the pedal you may hear the dislodged pieces of cat core rattling in front of the secondary cats. Putting the car on a lift would be best to isolate the point of rattle. If the source is at the front of the sec cat, the problem is likely the primary cat/s; if toward the center to back of sec cat would indicate the sec cat/s.
If you have removed the secondary cats, the debris from the primary cats will find its way to the exhaust exit. In this case you will start to see pieces of gray or whitish pieces of thin metal or ceramic material at you exhaust exit. If you rev the engine a few times, you may see particles on the surface behind the car; much more and larger if the secondary cats have been removed. I believe the OE muffler is a straight through design and will not stop debris unless it is a fairly large chunk.
Since you can occasionally hear what I think you're saying is a light rattle, I would guess your secondary cats are still in place. If you do quick revs, to about 1200-1400 RPM then quickly let off the pedal you may hear the dislodged pieces of cat core rattling in front of the secondary cats. Putting the car on a lift would be best to isolate the point of rattle. If the source is at the front of the sec cat, the problem is likely the primary cat/s; if toward the center to back of sec cat would indicate the sec cat/s.
05-08-2020, 06:51 PM
#3
Junior Member
Thread Starter
I would suspect the cats; because of the smell and the clinking sound. It may be that the primary cat has partially gutted itself with pieces of its core bouncing around at the input to the secondary cats. The performance may improve because of the initial increased air flow due to the deteriorating primary cat/s. As the debris collects at the input to the secondary cats performance will deteriorate.
If you have removed the secondary cats, the debris from the primary cats will find its way to the exhaust exit. In this case you will start to see pieces of gray or whitish pieces of thin metal or ceramic material at you exhaust exit. If you rev the engine a few times, you may see particles on the surface behind the car; much more and larger if the secondary cats have been removed. I believe the OE muffler is a straight through design and will not stop debris unless it is a fairly large chunk.
Since you can occasionally hear what I think you're saying is a light rattle, I would guess your secondary cats are still in place. If you do quick revs, to about 1200-1400 RPM then quickly let off the pedal you may hear the dislodged pieces of cat core rattling in front of the secondary cats. Putting the car on a lift would be best to isolate the point of rattle. If the source is at the front of the sec cat, the problem is likely the primary cat/s; if toward the center to back of sec cat would indicate the sec cat/s.
If you have removed the secondary cats, the debris from the primary cats will find its way to the exhaust exit. In this case you will start to see pieces of gray or whitish pieces of thin metal or ceramic material at you exhaust exit. If you rev the engine a few times, you may see particles on the surface behind the car; much more and larger if the secondary cats have been removed. I believe the OE muffler is a straight through design and will not stop debris unless it is a fairly large chunk.
Since you can occasionally hear what I think you're saying is a light rattle, I would guess your secondary cats are still in place. If you do quick revs, to about 1200-1400 RPM then quickly let off the pedal you may hear the dislodged pieces of cat core rattling in front of the secondary cats. Putting the car on a lift would be best to isolate the point of rattle. If the source is at the front of the sec cat, the problem is likely the primary cat/s; if toward the center to back of sec cat would indicate the sec cat/s.
Just to clarify, it's no so much as a rattle sound. More like a metal dragging sound.
But the heat shield is fine so.. it could definitely sound like metal in a tin can. So yes you must be right.
Interestingly enough, the gain of performance is significant and in my case is a symptoms as you put together well. Wished I kept it this way though. I mean I'm pulling a 0 to 60 in 4 sec!!! Probably a bit less if I'd disable traction control. That baby flies...
Is it bad or dangerous to drive in the meantime?
Btw why don't I have any engine light on on my console or codes in the scanners?
Thanks
Last edited by alexandergreat; 05-08-2020 at 07:01 PM.
05-08-2020, 09:15 PM
#4
MBWorld Fanatic!
Regarding no CEL, it may be just a matter of time or the O2 sensor/s could be defective. If the car has been tuned, detection of the problem may be disabled.
I don't believe there are any issues to be concerned about with driving it. I wouldn't take it on a long road trip however because if it is the primary cat/s and the core dislodges, it will stop at the secondary cat and will likely clog it and thus one bank almost completely. You would have a very slow ride back home..
I have some experience with metallic core cats. Some have the metallic fins wound on a stem which is welded to the enclosure. If the core is flopping around on one connect point, it will eventually break loose and clog things up; unless you're really lucky and it stops downstream in a way that exhaust can still flow.
I never advise anyone to delete cats. Your secondary cats will help with the pollution some but they just don't get hot enough quickly enough to be sufficient to meet standards. The other problem would be removing the debris when the primary stop shedding. If my memory is correct, the OE config has a flange that is far downstream after the secondary cats so you would have to cut the pipe to clear. No reputable muffler/exhaust shop would open the pipes to clear it and not have to replace the defective/s. Performance shops are a different story though...
Let us know what you find as the problem and how you handle it.
I don't believe there are any issues to be concerned about with driving it. I wouldn't take it on a long road trip however because if it is the primary cat/s and the core dislodges, it will stop at the secondary cat and will likely clog it and thus one bank almost completely. You would have a very slow ride back home..
I have some experience with metallic core cats. Some have the metallic fins wound on a stem which is welded to the enclosure. If the core is flopping around on one connect point, it will eventually break loose and clog things up; unless you're really lucky and it stops downstream in a way that exhaust can still flow.I never advise anyone to delete cats. Your secondary cats will help with the pollution some but they just don't get hot enough quickly enough to be sufficient to meet standards. The other problem would be removing the debris when the primary stop shedding. If my memory is correct, the OE config has a flange that is far downstream after the secondary cats so you would have to cut the pipe to clear. No reputable muffler/exhaust shop would open the pipes to clear it and not have to replace the defective/s. Performance shops are a different story though...
Let us know what you find as the problem and how you handle it.
05-09-2020, 12:39 AM
#5
Junior Member
Thread Starter
Regarding no CEL, it may be just a matter of time or the O2 sensor/s could be defective. If the car has been tuned, detection of the problem may be disabled.
I don't believe there are any issues to be concerned about with driving it. I wouldn't take it on a long road trip however because if it is the primary cat/s and the core dislodges, it will stop at the secondary cat and will likely clog it and thus one bank almost completely. You would have a very slow ride back home.. I have some experience with metallic core cats. Some have the metallic fins wound on a stem which is welded to the enclosure. If the core is flopping around on one connect point, it will eventually break loose and clog things up; unless you're really lucky and it stops downstream in a way that exhaust can still flow.
I never advise anyone to delete cats. Your secondary cats will help with the pollution some but they just don't get hot enough quickly enough to be sufficient to meet standards. The other problem would be removing the debris when the primary stop shedding. If my memory is correct, the OE config has a flange that is far downstream after the secondary cats so you would have to cut the pipe to clear. No reputable muffler/exhaust shop would open the pipes to clear it and not have to replace the defective/s. Performance shops are a different story though...
Let us know what you find as the problem and how you handle it.
I don't believe there are any issues to be concerned about with driving it. I wouldn't take it on a long road trip however because if it is the primary cat/s and the core dislodges, it will stop at the secondary cat and will likely clog it and thus one bank almost completely. You would have a very slow ride back home..
I have some experience with metallic core cats. Some have the metallic fins wound on a stem which is welded to the enclosure. If the core is flopping around on one connect point, it will eventually break loose and clog things up; unless you're really lucky and it stops downstream in a way that exhaust can still flow.I never advise anyone to delete cats. Your secondary cats will help with the pollution some but they just don't get hot enough quickly enough to be sufficient to meet standards. The other problem would be removing the debris when the primary stop shedding. If my memory is correct, the OE config has a flange that is far downstream after the secondary cats so you would have to cut the pipe to clear. No reputable muffler/exhaust shop would open the pipes to clear it and not have to replace the defective/s. Performance shops are a different story though...
Let us know what you find as the problem and how you handle it.
You got it...that might take some time though
Thanks!
