# 2011 335D with Carbon Buildup and Hoofed Injectors



## robster10 (Oct 8, 2012)

Flyingman said:


> Quote:
> Originally Posted by robster10
> Generator joe doesn't point out that our cars use ULSD, compress, heat, our diesel fuel over and over everyday.
> 
> ...


Flyingman, diesel fuel has changed with its refinement. Maybe more variables involved with fuel processing, and quality from states/provinces here in N/A compared to older stuff. Like you said idle and low loads. Compare the 335d to a smaller diesel motor ie. vw 2.0l which gets more of a workout. I doubt the 3.0l gets the same type of workout that the smaller motor does. Curious to see how the little 4cylinder 428d works out in the next 4 yrs?


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## floydarogers (Oct 11, 2010)

robster10 said:


> View attachment 444170
> My thoughts/concerns are with fuel turnaround, contamination at fuel stations. I fill up at truck stations most times because of this. We just don't get the turnaround at the diesel pumps that the gas pumps do. I will get some pics this summer when I do some prev. maintenance. My statement on shelf life between ulsd/gas. must be read as stated, since usld contaminates easily it deteriorates at a higher rate compared to low sulphur diesel, reg diesel and gas. Old type of diesel lasted many years since less refinement and additives in processing. 4th fuel filter on your car. (20k interv) yet injectors clogged, did they explain why they are plugged or just replace? My comments on BMW techs/mechs N/A comes from observations on this forum of how in statements some dealers gave diff info to some on intervals for fuel filter replacement- age of oil or mileage between oil changes. Fuel injector(s) replaced not address the clogging problem. "Carbon buildup"- heard 40-50k was the magic no. but some have gone higher like yourself 80k others even higher and then there's the ones with no issues nothing at all. Many here have had the injector replacement but did they also replace the fuel filter to address the fuel contaminating the injectors leading to clogging? Its not just me here questioning the replacement of parts, to drive away only to come back soon with the SES light??? 2009 was the intro of this 3.0l diesel here in N/A in a decent volume. How much experience have they gained in that time compared to a diesel fleet, commercial, mech. or other diesel owners with past experience? I asked at two of my local dealers if there mechs were specific diesel mechs? Answer "master technicians work on both gas & diesel, since we don't have many diesels here compared to gas versions". Difference to me is less experience diagnosing problems and correcting them. "Compressor fuel tank option". Yes diesel fuel is compressed by the pump, into the rails, shot out of the injectors, unused diesel is sent back into tank. This cycle happens over and over. Heat is built up with this process, by product of the fuel cooling is condensation, fuel degrades, contaminates, poorer burn of fuel, filter fails, injectors get plugged up more soot going back in through egr what a process. Maintenance is a key to a diesel motor as well how its used. I just have past and present experience of my own but mostly others who do this for a living to thank."Snarky reply" really? Don't be so sensitive! After all this is a forum. Take care, I will.


I didn't read your post because it's unreadable without line breaks.:thumbdwn:
Snarky comment: learn punctuation.:angel:


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## Nadir Point (Dec 6, 2013)

Flyingman, you got that all right as far as I know. I do in fact run fuel coolers in the return lines on my trucks and will also install something similar on the "D" in a future modification if I keep the car. But liquids are not generally speaking "compressible," as robster suggests, thus my compressor tank comment.

As far as hokey block-off and reset code procedures go, I don't consider that a viable approach - not my idea of doing it "right." The EGR system should be eliminated entirely, including the cooler and the computer coding modified to eliminate that portion entirely - done right.


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## DozerDan (Dec 18, 2013)

Nadir Point said:


> As far as hokey block-off and reset code procedures go, I don't consider that a viable approach - not my idea of doing it "right." The EGR system should be eliminated entirely, including the cooler and the computer coding modified to eliminate that portion entirely - done right.


Hokey?? Blocking off EGR systems is not new nor hokey. Truck guys to it all the time. It is arguably one of the best upgrades that can be done to any newer diesel truck. Far from hokey.


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## DaveN007 (Oct 4, 2013)

DaveN007 said:


> Please define "driving the D hard".
> 
> How hard do you have to drive it to achieve the following:
> 
> ...


I still want the guide for how to prevent CBU with my right foot.....

:dunno:


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## F32Fleet (Jul 14, 2010)

DaveN007 said:


> I still want the guide for how to prevent CBU with my right foot.....
> 
> :dunno:


I'm curious Dave.

What will you buy next? All electric or a Toyota? I only ask because every other manufacturer uses direct injection on their gassers and do require carbon cleaning approximately every 50k miles.


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## bimmerdiesel (Jul 9, 2010)

I was searching about Carbon build up for 335d and found this http://sfmslaw.com/class-action-lawsuits/cases.php?id=1500

I just crossed 56k mile mark and I feel I am not far from CBP issue. My mpg is gradually falling. Recent fillup was mere 25mpg where as I usually get 27-28 in summer months. At this point I want it to happen in another 20k miles so that I can recoup my investment on extended warranty and I can keep car longer.


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## DaveN007 (Oct 4, 2013)

BMWTurboDzl said:


> I'm curious Dave.
> 
> What will you buy next? All electric or a Toyota? I only ask because every other manufacturer uses direct injection on their gassers and do require carbon cleaning approximately every 50k miles.


My Porsche is DFI. Its family of engines are not having issues with carbon build up, so your premise is flawed.

It sounds like you understood when you bought your car that it would require the equivalent of thousands of dollars in engine cleaning every 50,000 miles or so and you were OK with this.

That is great. Especially considering that BMW didn't seem to have your insight.

My dealer certainly didn't mention anything about our engines needing cleaning every 50k miles. Not verbally or anywhere in the written material they shared with me.

My question was prompted the assertion that CBU was the fault of the driver. You are indicating that you agree with me that it is, in fact, a design issue. I simply want to know how to properly drive my car (according to the person who made the assertion) to lessen or eliminate CBU.

For example:

If you want to avoid door dings, you should park where other doors and other objects can't hit your car.

I am not sure what my replacement for the 335d will be. That will depend upon what is available when I want a replacement.


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## Nadir Point (Dec 6, 2013)

bimmerdiesel said:


> I was searching about Carbon build up for 335d and found this http://sfmslaw.com/class-action-lawsuits/cases.php?id=1500


This has no merit - just another ambulance chasing scumbag lawyer looking for easy money. BMW has released a service bulletin for it and is addressing the issue quite well, IMHO.

In fact, I was very pleased with the way Gebhardt BMW of Boulder, CO handled our case, despite being the first one they had seen. Just got the car back today after being with them for 8 days. Car feels strong again, got up to 34mpg on the drive home, mixed mode about 50/50 hwy/city. $3,500 BMW-cost parts, inc misc seals, gaskets, a new set of injectors and three oil changes by time it is completely finished 2 weeks from now. They changed it once after the repairs and again after some driving to flush out any walnut shells that may have got in there and asked me to bring it back again in 2 weeks for one more change. Did not reset the maintenance counters.

Can't say enough good about that. :thumbup:


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## bimmerdiesel (Jul 9, 2010)

I agree but what to do after warranty is over. BMW should do something more than just coming up with bulletin. 


Sent from BimmerApp mobile app


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## Nadir Point (Dec 6, 2013)

bimmerdiesel said:


> I agree but what to do after warranty is over. BMW should do something more than just coming up with bulletin.


Why should it be BMW's problem after it's out of warranty? If you can't afford either an extended warranty or maintenance costs, sell the car and get one that is less expensive to own and operate. I plan on doing things to work around the CBU problem in the near term and eventually eliminate the emissions equipmet that is causing the problem. By then it will be my spare toy car, so I'm not too worried about it any more.


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## bimmerdiesel (Jul 9, 2010)

You probably live in a state where there is no emissions check so you can think of bypass kits.

It's all theory of relativity when it comes to affordability. I don't like to spend 3500 on car which is 7yr old and 100k+ and worth 10-15k. I like to drive cars to ground before spending another 50k for new one. But this will be my first car which I ll get rid of before body or engine fails.
And I am not asking BMW to support car after warranty. Instead they should fix or advise owners on steps to avoid problem. Past 5 yrs I have been reading plight of owners who love their 335d but have to let it go just because they have no idea on how to avoid it.


Sent from BimmerApp mobile app


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## F32Fleet (Jul 14, 2010)

DaveN007 said:


> My Porsche is DFI. Its family of engines are not having issues with carbon build up, so your premise is flawed.
> 
> It sounds like you understood when you bought your car that it would require the equivalent of thousands of dollars in engine cleaning every 50,000 miles or so and you were OK with this.
> 
> ...


Well I'm at 65k miles and I haven't had to deal with CBU, but we all know build up is there. As for the Porsche DFI engines apparently some do suffer from it. http://forums.rennlist.com/rennforu...nt-have-direct-injection.html?referrerid=8132

As a whole I would expect Porsche to not have significant numbers with this problem under the assumption that more of their cars are tracked or wrung out.

The best way to not drive the car, or any gas / diesel car for that matter, is to short trip it.


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## DaveN007 (Oct 4, 2013)

BMWTurboDzl said:


> Well I'm at 65k miles and I haven't had to deal with CBU, but we all know build up is there. As for the Porsche DFI engines apparently some do suffer from it. http://forums.rennlist.com/rennforu...nt-have-direct-injection.html?referrerid=8132
> 
> As a whole I would expect Porsche to not have significant numbers with this problem under the assumption that more of their cars are tracked or wrung out.
> 
> The best way to not drive the car, or any gas / diesel car for that matter, is to short trip it.


I should be immune to CBU then.


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## JAPearson (Sep 9, 2011)

*2009 no CBU yet*

my 335d has 96k miles on it and is not exhibiting CBU. I used to sell Mack trucks years ago and noticed when they put out the most soot. So...now I drive the 335D imagining what the exhaust would look like without all of the emissions. It manifests in these ways;
1) I don't idle it when cold but slowly drive it away
2) make sure I always squeeze the pedal and not stab it as to not create an overfuel situation
3)I like to take is out on the interstate in areas where I think will be without troopers and light traffic and pull from 60mph in 4th to 120mph+in 5th and uphill is best. 
4) try to cruise at 80+mph indicated
5) not start the car for the day unless it get used more than once or goes on a trip longer than around town.
6) I do use fuel conditioner but don't say that it makes a difference, I can notice a little less rattle when in cold weather on start up below 32f.
I went in to the dealer and the foreman went out with me to road test to see if he could tell a foreshadowing of a CBU but he could not sense it. That being said I will probably throw a code this week!:dunno:


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## DaveN007 (Oct 4, 2013)

JAPearson said:


> my 335d has 96k miles on it and is not exhibiting CBU. I used to sell Mack trucks years ago and noticed when they put out the most soot. So...now I drive the 335D imagining what the exhaust would look like without all of the emissions. It manifests in these ways;
> 1) I don't idle it when cold but slowly drive it away
> 2) make sure I always squeeze the pedal and not stab it as to not create an overfuel situation
> 3)I like to take is out on the interstate in areas where I think will be without troopers and light traffic and pull from 60mph in 4th to 120mph+in 5th and uphill is best.
> ...


First...knock on wood...no codes for you. 

But seriously...you are making an argument for never getting a diesel car.

You should be able to get in the car and drive it without resorting to voodoo.

Correct me if I am wrong, but there is no such thing as "stabbing" versus "squeezing" when the car electronically meters the amount of fuel in response to throttle input. We don't have a cable running to a butterfly valve. Or do we ? :dunno:


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## starrfyr (Jun 5, 2012)

DaveN007 said:


> First...knock on wood...no codes for you.
> 
> But seriously...you are making an argument for never getting a diesel car.
> 
> ...


My $.02. I've read about CBU for years. In fact, because of all of the noise I almost backed out of the deal on my car. My car was acquired on a lease just after Thanksgiving of 2011 and is set to be bought out, in cash, in less than 30 days. So, CBU has been on my mind.

I had my car in the shop for diagnostic work on an issue completely unrelated to CBU recently. But, because CBU is the whipping boy for all problems related to the 335d I had to talk with the shop foreman about it. They replaced all 6 of my injectors and glow plugs (they were fine, the replacement was diagnostic) and checked for CBU. Not a trace of it was found in my wonderful machine. So, I'll tell you what the shop foreman told me, "However you're driving that car, keep doing it."

How do I drive my D? I have 2 simple rules; I NEVER hog on the pedal with a cold block or let a cold block idle. I drive easy and steady and wait for the block to warm up and THEN I beat the living **** out of it. These are easy rules and anyone that wants a D, BMW or otherwise, has to abide by them. If you can't, go buy a gasser. Not a trace of CBU means I'll be completing the lease buyout and, no, I will not buy an extended warranty.


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## JAPearson (Sep 9, 2011)

DaveN007 said:


> First...knock on wood...no codes for you.
> 
> But seriously...you are making an argument for never getting a diesel car.
> 
> ...


Just the basic design of a diesel is to add fuel to combustion chamber first then everything else kicks in after the fuel increases. BMW I am sure spent a lot of time trying to figure out how to limit an over fuel situation but it is just the nature of a diesel beast. I guess if you could get the same torque and mileage and longevity out of a gasser then I would be convincing people not to buy a diesel. However the diesel benefits are quite addictive. I also do not drive hard until the block is warm and am actually going to put a grill cover on the front for next winter. The car just likes to be warm


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## Nadir Point (Dec 6, 2013)

JAPearson said:


> Just the basic design of a diesel is to add fuel to combustion chamber first ...


You need to consider the basic design of the emissions control systems on these cars if you wish to add anything of value to this thread. Pumping exhaust and blow-by into the intake is what causes this problem. It's really pretty simple. Any 335D driven in a mixed-mode or primarily city-type environment will suffer CBU. The driven environment only sets the time it takes. Highway speeds create enough intake velocity and minimal EGR to hold it off. I wouldn't be surprised if a highway-only 335D developed CBU eventually anyway, just taking alot longer.


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## Flyingman (Sep 13, 2009)

Nadir Point said:


> You need to consider the basic design of the emissions control systems on these cars if you wish to add anything of value to this thread. Pumping exhaust and blow-by into the intake is what causes this problem. It's really pretty simple. Any 335D driven in a mixed-mode or primarily city-type environment will suffer CBU. The driven environment only sets the time it takes. Highway speeds create enough intake velocity and minimal EGR to hold it off. I wouldn't be surprised if a highway-only 335D developed CBU eventually anyway, just taking alot longer.


I would add that diesel engines with no EGR or DPF can suffer from CBU due to the valve overlap. At low load there is little charge air pressure from turbo and exhaust gas can back out into the intake through the intake valves at that moment in the cycle when the exhaust and intake valves are both open. This is one reason why you really should avoid low load conditions on any diesel for extended periods of time. The EGR and emission controls only compound the problem.


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