04Fire

Here's the top of the valves (same motor):


In answer to splinter's question... this motors at a local shop.

Glyn M Ruck

Not terrible but not wonderful either. Why was the engine stripped is splinter's question. Pity out of focus on tulip. Benz might have to think again for US market fuel. If the combustion chamber is anything to go by I suspect this car has been run on non additised fuel.

Jaywalker

I wanted to thank MBRedux by private message for his work on elevating this issue, but am unable to send him one. Thank you. I don't know whether or not you "saved" me $40k US, but I'm concerned enough by the lack of MB forthrightness on the matter to buy something else until the issue is resolved. I think I'll buy something used, and with port injection, so maybe the "savings" will only amount to $10k US, +/-. Kevin, thank you, too.

MDMercedesGuy

How can MB have a lack of forthrightness on something that we don't even know is an issue yet?

These engines have been on the road for a year now in the US and we have yet to see one with a definitive problem that can be tied to DI on here. The proof is in the pudding - and so far our bowls are empty on here.

DI is to Port Injection as Fuel Injection is to the carburetor. The technology cannot be run away from forever.

Jaywalker

That's a reasonable point - one cannot prove a negative. Given, however, a reasonable concern with DI intake valve build-up on other engines, I would have been happier with an MB discussion re "This is the way we avoided that particular trap," rather than platitudes such as "Trust us," or, "We haven't seen a problem." Of course they haven't seen a problem yet with new engines - they're still very new.

As one who embraced FI in the early days - J- and K-Jetronic, I believe, I watched each design improve on the previous. It's not hard for me to believe that the industry might overlook something on DI. I agree DI is the future, but I almost forgot for a moment my dictum of allowing others to purchase a first-year model in my anticipation of my first Mercedes. I'll wait for next year. That doesn't mean everyone should, of course.

amcguru

I guess a bottom end knock from worn wrist pin bushings

kevink2

Glyn,

If this is repeated on another W204 DI engine, would this open the door to a Solvent cleanout like Seafoam every 20-30K?






Ideally it would be let in just after the TB, to have a chance of even distribution.

.

Acapulco Bill

@kevink2: Really? You would actually do this to your CGI engine? One wonders how much of that smoke in the video, even after driving "around the neighborhood", is actually the plastic and rubber dissolved by the alcohol solvent dumped into the air intake system?

Perhaps reading of all that VIS technology has in its intake system will dissuade some from attempting this methodology.

http://en.wikipedia.org/wiki/Variabl...ntake_Manifold

kevink2

@Bill: Does my quote sound like I'd just grab a can and do it? "If this is repeated on another DI engine, would this open the door to a Solvent cleanout ?" If it does, it was not intended.

It was just a concept that came to mind after seeing the build-up at relatively low miles. Of course I would not suggest anyone doing it without researching the method, possible degradation of plastics (note about 90% of the smoke is just volitiles that pass through having done nothing. A few points to check:

1) before & after pics of back of intake valves on MB engine
2) chemical compatibility with plastics used on MB engine
3) cylinder damage due to solvent washing of walls.

Not sure of the purpose of your link, plastic parts in the tumble valve assembly, with semi throttle plates in each runner?

I does look like it contains Isopropanol, among other goodies. Seafoam MSDS

By now with all the DI engines out there, there may be other cleaners that are compatibile, if Seafoam is not.

The other option is to rely on the targeted spray from the injectors, that hit the back of the valve for a few ms, and use Techron. Logically it would be best to prevent the builup, rather than try to remove it.

.

Acapulco Bill

The jury is still out on substantial evidence that this buildup is a problem on the MB CGI engines. 04fire's photos of the head in Post #197 looks pretty normal especially if the car was driven around town or in traffic just prior to their removal, and as post #202 suggests on inspection of post #201's picture, this may be due just to a particular gasoline's quality or a problem with the crankcase recirculation valve.

Obviously some DI engine manufacturers also agree with kevink2 that prevention is the cure, for instance VW is already reengineering radical solutions to their DI engine problems, basically mounting a second set of the older non-DI injectors used only during acceleration to wash the back of the intake valves, turning them off during constant RPMs.
A very complex and costly solution.

However this situation can be a result of VW's particular valve and ignition timing and also of the amount of agitation and temperature of the oil by the crankshaft, as these deposits are caused from recirculated oil vapors. One wonders if DI engines with an oil dry-sump are subject to these deposits?

Glyn M Ruck

I'm travelling. Will take a close look on my return 9th.

kevink2

@Bill: I was mostly focused on the back of the intake valves, not the piston tops where the build-up is flacky, as you said. VW/Audi was likely still sore from the reaming they got from the kazillion I4 turbos that sludged up on them, and required expensive remediation.

I was not thinking of the VW hi & low pressure injectors, as far as prevention methods. I assumed that the MB DI method of cleaning the back of the intake valves, was to angle the injector to hit the back of the partly opened valve @ overlap. This was the consensus of opinions, as I recall. My thought was to use this oem amount of fuel wash, and just add Techron or some equal or better detergent to the tank, to keep valves cleaner.

I do think that Seafoam was sucessfully used for the 2006/7 Mazdaspeed6 I4 Turbo, with a similar dual flow intake system. I'll have to check on that to verify.

.

Acapulco Bill

I am unaware that MB had even addressed the potential problem with the CGI, as to alter the location or spray angle or pattern of the injectors defeats the purpose of DI. (Let's just say it would have been a good trick for MB engineers to have foreseen the problem and resolved it in this way).

Let's wait for Glyn's take on this, he may have more case histories (or not) that point to a potential or nonexisting problem. Fords new 3 cyl. 1.0L addresses this with a novel solution, I understand.

MBNUT1

Is this not evidence (out of focus perhaps) of the DI inlet valve fouling concern?

kevink2

Glyn's take is peppered throughout the thread, as is MBRedux's, along with lots of great graphics. Rather than ask Glyn to repeat himself, I suggest you read this moderatly long, very informative thread. Some key posts are 115, 130, and 183, among others.

At some point, Glyn mentions that MB knew about valve carbon build-up in other DGI models (likely back in the VW and Mazdaspeed6 (2006) years). He said MB came up with a plan that included back washing the intakes, and did proof tests in SA with long runs and no valve build-up.

It's somewhere in this thread, but I met an older, classy asian man in a 3 piece suit at the Philly Auto show last winter. I was eye-balling the cross sectional engines at the show, focused on the DGI engines. I met this guy when I was at the I4 Ford eco boost engine. He had a brief case and was taking notes as he observed engines. He had missed the open combustion chamber, hidden at the rear of the display, so I helped him climb on the display trailer to see it. We talked, and he was a fuel injection consultant for Ford. I explained the Mazdaspeed6 major problem with DGI. He mentioned timing of the injector, angling it, and pushing for better fuels in the US. So your Ford may be free of the problem.

.

leehotung

Just an quick update from China. Recently Mercedes release an "ecu upgrade" for the 1.8L M271evo engine. The package involves a ECU "upgrade" and change of spark plugs. The spark plug change interval (after the "upgrade") reduces from 6 years to 2 years. In a Chinese forum, some said the cars became smoother and some said it became less powerful. I have my car checked in but do not feel any change after the "upgrade", knocking still presence when i accelerate from low rpm / high gear. Using manual change is still most effective for me, just keep my fingers crossed the fuel quality in China will improve before I sell the car.

Cosworth2000

I have a solution for this so that it will not happen.

Carbon is always from incomplete turn. We have to remember that DI burn hotter and as such if you do not prevent water build up in the tank, this will be a problem.

Also may people I see put hazardous chemicals into their engines in hopes to keep this from happening.

If you would like more information on how to prevent this, let me know as I can help you.

Take note that Ethanol that is most gas these days loves water. Water in the fuel is the enemy for all engines wither they be old or new.

I also have a Mazda which when my old club came to assist me in changing the spark plugs seen for the first time that what I do works as I had the cleanest intake manifold that they have ever seen.

I do the same protection with my MB both the C Class and the ML350.

No problems, no headaches

Glyn M Ruck

??????

The deposits are from asphaltenes & other impurities etc. in the fuel, oil vapours from captive breathers & oil coming down valve guides. Mainly burnt VI Improver.

They have nothing to do with water.

dcjwlee

Geez, I just picked up my '13 GLK350 tonight and this thread has kept me up all night! I need to be up in a few hours!

I didn't have the will to read through all the pages when I had the C300, but now that I have a DI GLK 350 I read through every single page.

Still not sure what to expect though!

Acapulco Bill

C300 is not direct injection. To date there has not been widespread reports of carbon buildup in MB DI engines, as there definitely is in VW/Audi products. Don't lose sleep over this.

In any case, as Glyn M. Ruck has pointed out, much has to do with keeping up-to-spec oil and not using deficient gasoline (although of course the gas is an indirect cause of this syndrome, as the fuel itself never enters the intake system).

Attention should be given to the crankcase vapor recirculation system, perhaps MB has already has a bulletin about preventive measures (anyone?).

dcjwlee

Thanks, Bill. I'll try not to!

RLE

Why don't you forget all this and get on with your life? You have a new car with a warranty for the next four years.

Let somebody work themselves into a state of panic.

klobbr

Just curious. Breaking in our 2013 e350 Sport wagon that we've had for a week. Love this car. And have an extended warranty in place just in case.

Best,
Bob

spyked

I'm anxious to see how the 3.5 DI (new M276 motors) do compared to the M271 Evo. As I understand it (could be wrong...), the M276 series are NEW engines, most likely developed with DI in mind.

The M271 is well over a decade old (almost two decades?). They just replaced the supercharger (kompressor) with a turbo and added DI and re-introduced it to U.S. market.

I'm thinking that the C300/C350 models with DI will do better than the M271 Evo (C250 CGI in U.S.) in terms of carbon build up.

At least the I4 in the new CLA is a new engine series. Designed from ground up with DI in mind. It's us M271 Evo owners (only for 2012 and 2013 in U.S.) that MIGHT have a problem. As I see it anyway....

MDMercedesGuy

I'd think at this point if we were going to start seeing problems, we would by now.

I'm at 13 months and 11K miles with no issues so far. The car only gets 91 or 93 octane and averaged 24.1MPG combined over the last 10 tanks. I reset the trip computer at 1,000 miles on it and have not touched it since and it reads 23.4MPG over the last 10K miles.

In the US, the car is not known as the C250 CGI. It's just known as the C250 - providing wonderful loads of confusion for our neighbors to the north who have C250 V6es...