[F32Fleet]

Originally Posted by Jhayd11

Thanks SOCOM. I am told by BMW mine has intake, EGR, and turbo plugged up. I am assuming because it went on for so long without proper diagnosis.

Have them take photos.

[acewiza]

A twin-turbo excessively emissions-managed diesel with EGR is a carbon build-up nightmare waiting to happen. Everything on the exhaust side (Turbos, DPF, CAT) is subject to clogging whenever non-optimal combustion is present for any reason for any extended or routine period of time. This could involve anything from short trip driving to sensor malfunctions and/or mis-calibrations and other things in between.

Then you pump it back to the intake with EGR and the viscous cycle continues and amplifies. Drive it hard and keep your fingers crossed. Fuel additives are not going to do anything for this situation. Emissions deletes and water/meth are the only true solution(s).

[F32Fleet]

Spoke to two technicians about carbon. The buildup occurs at about 60k miles at the intake ports (sometimes on exhaust side) not the intake runners or the EGR valve. Apparently this is a very small area. This issue is more prevalent with the 335d vs X5d.


They also said meth will not work unless it was injected right at the ports which would be difficult to arrange.


On side note it feels good to have oil, coolant, and brake fluid done.

Here is a link to a cylinder head. As you can see the ports are small.

http://www.bmwheaven.com/index.php/c...-cylinder/m57#

[Jhayd11]

Talked to my rep, they confirm 335d is more likely to have issues than the X5d. They theorize that the X5 requires a bit more from the engine, giving it the advantage of using the full rev more.

Still, I will say whether or not the carbon build should... it HAS messed with my EGR and turbo. I didn't take pictures, phone was dead, but I asked the service rep to document items as they go.

[Puerto Rican 335d]

I gather thats why some of us TUNED vehicles are less prone to this but I might be wrong also.

[F32Fleet]

Originally Posted by Puerto Rican 335d

I gather thats why some of us TUNED vehicles are less prone to this but I might be wrong also.

Maybe on the intake side if the tune closes off the EGR. The exhaust valves and turbo are still subject to the over fuel from the tune.

[335dFan]

CODs (Concerned Owners of Ds)

You know, there seems to be a lot of varying opinions on what various things could be done to lessen the rate of carbon build-up. One of the things that is bandied about is driving the car hard. Hard like spending 30 minutes a day at Autobahn speeds, with an occasional half-to-all-day jaunt through the Bavarian countryside on E52.

Well, as great as that was long ago, it doesn't fit my current circumstances very well. So, I was wondering what you CODs would think about this as a palliative measure.

I'd say about 98% of the time my transmission is in D. When I go to the track, I put it in DS. Today on the way to work I decided to do a little manual shifting. I was playing around driving in M2 and M3 and noticing the RPM level. I was thinking that maybe regular (30 minutes a day or so or less) of keeping the revs up between 3000-4000 might not be a bad idea. Couldn't hurt right? Maybe a waste of fuel. Any possible benefit?

[acewiza]

Originally Posted by 335dFan

When I go to the track, I put it in DS. Today on the way to work I decided to do a little manual shifting.

Not a bad idea, at all. I use DS exclusively when driving the wife's 335D. I actually make a point of taking it out for whatever reason I can dream up at least once every couple of weeks for a good thrashing. High rpm and full heat cycles are IMHO, the only ways carbon build-up might be kept at bay in a stock 'D.

[Vreimann]

Originally Posted by 335dFan

CODs (Concerned Owners of Ds)

You know, there seems to be a lot of varying opinions on what various things could be done to lessen the rate of carbon build-up. One of the things that is bandied about is driving the car hard. Hard like spending 30 minutes a day at Autobahn speeds, with an occasional half-to-all-day jaunt through the Bavarian countryside on E52.

Well, as great as that was long ago, it doesn't fit my current circumstances very well. So, I was wondering what you CODs would think about this as a palliative measure.

I'd say about 98% of the time my transmission is in D. When I go to the track, I put it in DS. Today on the way to work I decided to do a little manual shifting. I was playing around driving in M2 and M3 and noticing the RPM level. I was thinking that maybe regular (30 minutes a day or so or less) of keeping the revs up between 3000-4000 might not be a bad idea. Couldn't hurt right? Maybe a waste of fuel. Any possible benefit?

This is quite a valid point. My D only see's continuous good highway speeds every 3-6 months and my current regime is 60-110km/hr and not over 15 minutes of driving.

Before I went on my long driving vacation, I will admit that my car didn't feel like it had any power at all. It started ok, but to drive off onto the street the throttle would hiccup on me for about 10 seconds before starting to improve. Before my trip the last long drive was 6 months previous and in -27c temperatures.

During the first hour of the vacation driving the car seemed to behave much better, and by the time I got back home, the car felt like a champ with no hesitation and I drove the car very hard especially climbing mountain passes.

I have started to drive only in DS as is does not seem to really give a fuel penalty, but with the reading I have been doing, the EGR position is a function of the torque produced and the rpm, and after 4000rpm the EGR is 100% closed so maybe this could help with some preventative maintenance.

[acewiza]

One of the problems with this vehicle (if you can call this a problem) is the thing has such a high power to weight ratio there is enough torque available for it to mope around just off idle in low speed or city driving, literally choking itself to death over time in the process, if you allow it to do that.

[joe_planet]

Originally Posted by Socom

Maybe on the intake side if the tune closes off the EGR. The exhaust valves and turbo are still subject to the over fuel from the tune.

I spoke with my tuner and the ecotune flash doesnt change anything to the egr duty cycle. This is because the dpf regeneration depends on it. Only when the dpf is removed do they change the egr duty cycle. I cannot speak for other tunes but I would assume they handle it in the same way.

[Hoooper]

Originally Posted by joe_planet

I spoke with my tuner and the ecotune flash doesnt change anything to the egr duty cycle. This is because the dpf regeneration depends on it. Only when the dpf is removed do they change the egr duty cycle. I cannot speak for other tunes but I would assume they handle it in the same way.

if im not mistaken, during regen the EGR is completely shut, so if they programmed it to be more frequently shut that shouldnt be a problem. Not saying you or ecotune are wrong, but their answer or reasoning doesnt make sense to me.

[F32Fleet]

Originally Posted by acewiza

One of the problems with this vehicle (if you can call this a problem) is the thing has such a high power to weight ratio there is enough torque available for it to mope around just off idle in low speed or city driving, literally choking itself to death over time in the process, if you allow it to do that.

Yep. It's akin to using a sledge hammer for cabinet work. Lol.

[joe_planet]

Originally Posted by Hoooper

if im not mistaken, during regen the EGR is completely shut, so if they programmed it to be more frequently shut that shouldnt be a problem. Not saying you or ecotune are wrong, but their answer or reasoning doesnt make sense to me.

I think you are right, maybe I should talk to ecotune themselves...
I did think about this and it didnt make much sense to me either, but this is what the tuner relayed to me.

[135i_vs_]

Tunes indirectly effect EGR operation. Tunes increase fuel, to maintain the AFR ratio, EGR valve operation is reduced to increase oxygen (air). Works perfect actually. You can have your cake and eat it too in this case.

[F32Fleet]

Originally Posted by 135i_vs_

Tunes indirectly effect EGR operation. Tunes increase fuel, to maintain the AFR ratio, EGR valve operation is reduced to increase oxygen (air). Works perfect actually. You can have your cake and eat it too in this case.

But your DPF pays the price.


No free lunch as they say.

[335dFan]

Originally Posted by Vreimann

I have started to drive only in DS as is does not seem to really give a fuel penalty, but with the reading I have been doing, the EGR position is a function of the torque produced and the rpm, and after 4000rpm the EGR is 100% closed so maybe this could help with some preventative maintenance.

Yesterday I drove for a while on I97 south in M4, which is the gear it took to get the RPM up to 3K and above at interstate speeds. Interestingly enough it didn't sound like it was working terribly hard even then. I haven't paid attention to what RPM I am seeing in D mode when I am up around 100 mph, so I can't say what 3-4K in M4 is equivalent to in top gear. But I can say that fussing around in DS and manually shifting (and of course goosing it more) definitely put a dent in my normal sterling MPG. As a general observation, where I normally get around 520 or so miles to a tank around suburban Maryland. For this tank I am presently showing around 460. It'll probably come back up a bit as I resume normal ops after my experimenting yesterday.

[Vreimann]

Originally Posted by 335dFan

Yesterday I drove for a while on I97 south in M4, which is the gear it took to get the RPM up to 3K and above at interstate speeds. Interestingly enough it didn't sound like it was working terribly hard even then. I haven't paid attention to what RPM I am seeing in D mode when I am up around 100 mph, so I can't say what 3-4K in M4 is equivalent to in top gear. But I can say that fussing around in DS and manually shifting (and of course goosing it more) definitely put a dent in my normal sterling MPG. As a general observation, where I normally get around 520 or so miles to a tank around suburban Maryland. For this tank I am presently showing around 460. It'll probably come back up a bit as I resume normal ops after my experimenting yesterday.

The diesel doesn't ever seem to be really working on the interstate. Even climbing the mountains the car kept accelerating up to 140 so I am not sure. It just wants to go fast and it likes it.

[135i_vs_]

Originally Posted by Socom

But your DPF pays the price.

I've thought about this...not really sure how much more exhaust gases are really being filtered by the DPF, I can't imagine it being significant, as this quantity is supposed to be recirculated into the engine. I would hope the DPF can handle a little more.

[Hoooper]

yeah, the only DPF taking a beating i would expect to be from tuning. For the EGR unless you are concerned from a heat standpoint the particulate count from a closed egr should be the same as an open one since the particulate isnt being burned on the second trip through, its already burnt. i believe Tdiwyse found that closed actually has lower exhaust temps even though that doesnt really make sense

[dixy2k]

Originally Posted by GTGuy

Year: 2011
Model: 335d
Mileage: 36,000 miles
MPG: 35.6
Avg Speed: Don't check
Brand of fuel: Sunoco
On a scale of 1 to 5 how hard do you drive? 3
Highway: Mostly highway
Carbon build up issue yes or no? No

I think you posted in the wrong thread.

This is a better one: http://www.e90post.com/forums/showth...6#post15033916

[hrc630]

Originally Posted by Puerto Rican 335d

Seems like 2 out of 24 posts with carbon build up, not bad, but interestingly most of us who beat the car like a two cent whore dont have any problems as of yet with carbon build up, its suffice to say that our cars have to be driven HARD so that this issue cannot come later. What do you think Chris on this?

I can tell you that i can't beat my car more. I push her to 120 mph EACH day, i go to the dragstrip, make 1 mile race, have JBD à 100% and my car is
at the garage since 3 week for severe carbon build up New head, intake, injectors +++

Your car only have +- 30,000 miles so its normal that you dont have carbon build up. My car run like a champ until 60,000 miles... You can beat it, put whatever you want (tune, additive, etc) you will have carbon build up as soon as you approche the 60,000 miles mark

The mecanical advisor tell me its a bad design egr/emission system and and the carbon build up is inevitable. Its bad, but its the reality.
i am certain that each 335d will suffer from carbon build up before the 100,000 miles mark.