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New DI Engines -- Excessive Carbon Buildup ??

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Old 06-10-2015, 06:49 PM
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New DI Engines -- Excessive Carbon Buildup ??

 
Old 05-09-2017, 08:28 PM
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Originally Posted by mleskovar View Post
Yes I noticed where you blanked off the EGR path. How many miles have been put on motors since you've done this? Where does the crankcase pressure vent? Any follow up investigation? No doubt that rail injection cleans the valves.
.
Just as a FYI, this was done by multiple people on vwvortex forums for the 2.0TFSI engine. I'm sorry that I don't remember what was the end result, but it was NOT pretty. UOAs came in with poor results, but I don't remember what it was.

Anyways, the evidence presented was enough to keep me from doing that (not the EGR in that case, but the PCV return)
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Old 05-09-2017, 08:54 PM
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I've also read some articles about blanking the egr valve and seen before and after pictures that show less carbon buildup with it removed. First....without remapping the motor you'll use more gas without question and probably, not all cars, throw a CEL. Yes there is gas vapor in the crankcase but no where near the amount that passes the intake valve before it closes. That's why valve timing and piston crown changes (charge swirl) have such a big effect on the carbon buildup. I am neither an expert nor a scientist and don't claim to be.
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Old 05-09-2017, 08:57 PM
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Originally Posted by mleskovar View Post
I've also read some articles about blanking the egr valve and seen before and after pictures that show less carbon buildup with it removed. First....without remapping the motor you'll use more gas without question and probably, not all cars, throw a CEL. Yes there is gas vapor in the crankcase but no where near the amount that passes the intake valve before it closes. That's why valve timing and piston crown changes (charge swirl) have such a big effect on the carbon buildup. I am neither an expert nor a scientist and don't claim to be.
That's new info for me. No doubt there is less intake valve buildup, but what's the reason behind the 'using more gas' part? I'm most curious. Thank you
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Old 05-09-2017, 10:04 PM
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Originally Posted by superangrypenguin View Post
...what's the reason behind the 'using more gas' part? I'm most curious. Thank you
EGR valves come into play at low rpms. It dilutes the intake charge with more air/crankcase vapor which leans it out. Removed it takes in more gas because the intake pressure is constant and takes in the same volume of charge....it just has less vapor/air without the EGR to feed it.
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Old 05-10-2017, 06:24 AM
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Originally Posted by mleskovar View Post
EGR valves come into play at low rpms. It dilutes the intake charge with more air/crankcase vapor which leans it out. Removed it takes in more gas because the intake pressure is constant and takes in the same volume of charge....it just has less vapor/air without the EGR to feed it.
Thanks. Keep in mind though that EGRs don't exist on gas cars. Are you referring to the PCV system?
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Old 05-10-2017, 08:54 AM
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Originally Posted by superangrypenguin View Post
Thanks. Keep in mind though that EGRs don't exist on gas cars. Are you referring to the PCV system?
Hi,
Just to clear up any confusion block off the EGR valve (exhaust gas recirculation) this is what lets burnt exhaust fumes back in too the intake system.

By blocking it up this stops the exhaust fumes going in to the intake and in my experience with petrol and especially diesels works very well in eliminating carbon build up. Most cases the engine runs noticably smoother at light throttle after this mod.

My experience is with Diesels, carb petrol and port injection petrol in all these case the engine did not need any sort of tuning/ mixture adjustment after blocking off the valve.

Do not block off the PCV valve you will be in serious trouble with oil leaks.


Yes there are EGR valves in Mercedes petrol engines this link is one example, and if you look carefully at a photo of used one you should see carbon build up.

https://www.google.co.nz/search?q=me...&bih=689&dpr=2

Last edited by NZ-Merc; 05-10-2017 at 09:01 AM.
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Old 05-10-2017, 08:58 AM
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Originally Posted by NZ-Merc View Post
Hi,
Just to clear up any confusion block off the EGR valve (exhaust gas recirculation) this is what lets burnt exhaust fumes back in too the intake system.

By blocking it up this stops the exhaust fumes going in to the intake and in my experience with petrol and especially diesels works very well in eliminating carbon build up.

My experience is with Diesels, carb petrol and port injection petrol in all these case the engine did not need any sort of tuning/ mixture adjustment.

Do not block off the PCV valve you will be in serious trouble with oil leaks.


Yes there are EGR valves in Mercedes petrol engines this link is one example.

https://www.google.co.nz/search?q=me...&bih=689&dpr=2
PCV valves is what allows for exhaust gas to be recirculated back to be burned by another round of combustion. at least that's my understanding..

Anyways, for the Audi folks I used to chill/chat with, they just blocked the return back to the intake from the PCV valve.
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Old 05-10-2017, 09:08 AM
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PCV valve is (positive crankcase ventilation valve) and this is the valve which allows the fumes from inside of the sump/engine and any gasses which pass the rings to be vented in to the intake manifold.
I can not recall the theory exactly at the moment I think there is a slight pressure difference between the intake and crankcase which is controlled by the valve with a seating ball and light spring.
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Old 05-11-2017, 05:24 PM
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You can use an "oil can" system to catch the oil from the PVC system. It traps the oil in the can and allows the fumes to recirculate.
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Old 05-11-2017, 09:19 PM
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Originally Posted by tommiett View Post
You can use an "oil can" system to catch the oil from the PVC system. It traps the oil in the can and allows the fumes to recirculate.
WRONG. Have run catchcan for years and have done analysis on them. They make ZERO measurable difference to intake valve buildup in DI engines.

I probably went through 10 or so different ones on the A4. Did diddly poop

And PVC is for pipes in your house. I think you mean PCV
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Old 05-12-2017, 04:38 PM
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???

Originally Posted by superangrypenguin View Post
WRONG. Have run catchcan for years and have done analysis on them. They make ZERO measurable difference to intake valve buildup in DI engines.

I probably went through 10 or so different ones on the A4. Did diddly poop

And PVC is for pipes in your house. I think you mean PCV
LOL... So you used 10 catch cans or so and they did nothing? So it took you 10 or so catch cans to determine they did not work?????



Just giving you a hard time..........
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Old 05-12-2017, 04:47 PM
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Originally Posted by tommiett View Post
LOL... So you used 10 catch cans or so and they did nothing? So it took you 10 or so catch cans to determine they did not work?????



Just giving you a hard time..........
Tried ten different designs over the years. All failed.
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Old 05-12-2017, 05:26 PM
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Originally Posted by superangrypenguin View Post
Tried ten different designs over the years. All failed.
Did they collect some oil but didn't stop the carbon build up? The BMW forum went through the catch can "fix" with same results.
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Old 05-12-2017, 05:53 PM
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Originally Posted by mleskovar View Post
Did they collect some oil but didn't stop the carbon build up? The BMW forum went through the catch can "fix" with same results.
Oily watery goop. No it did not stop the carbon buildup. It's easy in my old car to take a look at the intake valve. All one needs is one screwdriver and a horoscope. I inspected them religiously across all 4 seasons every 5000km. there was no measurable difference.
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Old 05-13-2017, 10:47 AM
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Horoscope? Does it tell you something like "Today is a good day to see carbon buildup and romance is in the stars"?

Sorry, couldn't resist.
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Old 05-13-2017, 04:29 PM
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Originally Posted by Alfadude View Post
Horoscope? Does it tell you something like "Today is a good day to see carbon buildup and romance is in the stars"?

Sorry, couldn't resist.
What, you don't believe horoscopes?!?!



Lol yes, typing error.
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Old 02-19-2018, 01:40 AM
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Questions - DI C250 carbon buildup

Hi, new member here. Thank you to all who have shared their knowledge above - very interesting though a lot of it over my head.

I have a couple of questions, I'll keep it as succinct as possible. Though not mechanically knowledgeable, I have read through the thread and wanted to confirm my understandings. Apologies if I am asking stupid questions, that's why I am here - to learn.

2010 C250 CGI / 1.8L 4 cylinder turbo / direct injection / 150,000 km / Australia

-Car started "stuttering" under power repeatedly resulting in Check Engine Light and limp mode.
-MB Dealer diagnosed excessive carbon buildup in air intake manifold
-Intake manifold cleaned and one ignition coil replaced by MB Dealer. Car returned.
-Though much better the car still "stutters" under constant power as it did before.
-Car now booked into MB Dealer to resolve.

When the car was returned I asked specifically whether the air intake valves had been cleaned. MB Dealer replied "No, they did not need cleaning".

My question is this: If there is excessive carbon buildup in the air intake manifold would that not also mean there is excessive carbon buildup on the air intake valves, meaning they also need cleaning via walnut shells or otherwise? Or am I wrong?

I guess what I am wondering is - did this guy (MB Dealer) lie to me when they had done only half the required job.

Thanks in advance for your help. WilliamH
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Old 02-19-2018, 09:43 AM
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Originally Posted by WilliamH View Post
Hi, new member here. Thank you to all who have shared their knowledge above - very interesting though a lot of it over my head.

I have a couple of questions, I'll keep it as succinct as possible. Though not mechanically knowledgeable, I have read through the thread and wanted to confirm my understandings. Apologies if I am asking stupid questions, that's why I am here - to learn.

2010 C250 CGI / 1.8L 4 cylinder turbo / direct injection / 150,000 km / Australia

-Car started "stuttering" under power repeatedly resulting in Check Engine Light and limp mode.
-MB Dealer diagnosed excessive carbon buildup in air intake manifold
-Intake manifold cleaned and one ignition coil replaced by MB Dealer. Car returned.
-Though much better the car still "stutters" under constant power as it did before.
-Car now booked into MB Dealer to resolve.

When the car was returned I asked specifically whether the air intake valves had been cleaned. MB Dealer replied "No, they did not need cleaning".

My question is this: If there is excessive carbon buildup in the air intake manifold would that not also mean there is excessive carbon buildup on the air intake valves, meaning they also need cleaning via walnut shells or otherwise? Or am I wrong?

I guess what I am wondering is - did this guy (MB Dealer) lie to me when they had done only half the required job.

Thanks in advance for your help. WilliamH
Hi William

Welcome to the forum. I don't think you'll get a lot of info from us on this thread because this thread is specifically talking about excessive carbon buildup on direct injected gasoline cars. I believe your cgi is a diesel, and thus most of us don't have any experience working with that. Hopefully someone else can chime in here. Personally, I'd start another thread instead of posting in this one if in fact your car is a diesel to get you the eyeballs necessary to help you resolve your issue.
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Old 02-19-2018, 03:33 PM
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Originally Posted by superangrypenguin View Post
Hi William

Welcome to the forum. I don't think you'll get a lot of info from us on this thread because this thread is specifically talking about excessive carbon buildup on direct injected gasoline cars. I believe your cgi is a diesel, and thus most of us don't have any experience working with that. Hopefully someone else can chime in here. Personally, I'd start another thread instead of posting in this one if in fact your car is a diesel to get you the eyeballs necessary to help you resolve your issue.
CGI stands for Charged Gasoline and the 2010 C250 CGI has the M271 DE18 engine which is a direct-injection gasoline engine.
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Old 02-19-2018, 06:16 PM
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Originally Posted by xsever View Post
CGI stands for Charged Gasoline and the 2010 C250 CGI has the M271 DE18 engine which is a direct-injection gasoline engine.
Thanks for the info. In that case yes the dealer is wrong.
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Old 02-19-2018, 08:33 PM
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Originally Posted by xsever View Post
CGI stands for Charged Gasoline and the 2010 C250 CGI has the M271 DE18 engine which is a direct-injection gasoline engine.
Thanks xsever, beat me to it.
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Old 02-19-2018, 08:34 PM
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Originally Posted by superangrypenguin View Post
Thanks for the info. In that case yes the dealer is wrong.
Hi superangrypenguin. Thanks for the welcome and information.
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Old 02-21-2018, 06:05 PM
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Hello guys, I previously posted a new thread regarding a check engine light that seems to occur occasionally. I have a C250 with the 1.8 4 cylinder turbo (M271 EVO) car does have a lot of miles.

However, I don't know how to diagnose if it is suffering from carbon build up. After I park the vehicle I do smell a weird mixture of oil/gas and the exhaust pipe sometimes smokes a bit longer.... Most of the time the car is fine. I at first attributed to the cold New England weather but it persisted throughout warmer days.
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Old 04-20-2018, 09:51 AM
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Originally Posted by Glyn M Ruck View Post
I agree - Catch cans are a WOFTAM.

The only time I have seen one work was on a very worn M111 where blowby was excessive & the Benz separator could not keep up with all the oil in the inlet system.

The corrective action should have been an engine rebuild.

Question.... I've been watching vids and researching online line for the past 3 months now about Oil Catch cans... From what I can see, they do work. However, from what I am reading on this forum about people's opinions that they do not work... The thought crosses my mind on whether or not those who bought a OCC, could have just bought the wrong kind or too cheap of an OCC? There are many types on the market and from what I've seen many would not work properly IF they don't have that filter, mesh or divider inside of the can. So I'm wondering if those who had problems with their OCC, if they may have just needed to get a better quality OCC?
I ask this question because from my research, I've found that, YES, there are inherently known issues with OCC's that don't have the right separator or filtration systems inside of them (meaning oil and water going past the can and into the intake manifold) all because the OCC's they had were nothing but an open empty can. OR because some people had let the can fill up to the point where the contents leaked out into the intake system.

Just a thought
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