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Carbon Build Up a 335d issue?

42K views 128 replies 47 participants last post by  DnA Diesel 
#1 ·
As I wade through the results of a search for "carbon" in the diesel forum, the discussions carbon build up predominantly refer 335d's, much more so than to other BMW diesels, e.g. the X5d.

Is this impression correct? If so, since they are essentially the same engine, is there an explanation for why this would be an 335d issue but not an X5d issue?
 
#46 ·
2011 335d and current carbon buildup

Bought a 2011 335D with about 15k on it and has run like a champ until recently. At 35k, the car began to stumble. I had done some reading here about carbon buildup, and suspected that I may one day see this problem. Took the car to Bellevue, BMW, in WA and the car had so many codes that did not relate to each other that they had to send in a request to BMW engineering for advice. Apparently new 'parts' are coming, don't know what they are yet. Still driving the car, although it is not running 100%. Am wondering what the parts will be, and will be asking more questions when they arrive. They will keep the car for a few days for some kind of rebuild. Will post more notes at the end of next week, once the work is completed. Dealership doing a great job so far and the car is still under warranty.
 
#50 ·
Bought a 2011 335D with about 15k on it and has run like a champ until recently. At 35k, the car began to stumble. I had done some reading here about carbon buildup, and suspected that I may one day see this problem. Took the car to Bellevue, BMW, in WA and the car had so many codes that did not relate to each other that they had to send in a request to BMW engineering for advice. Apparently new 'parts' are coming, don't know what they are yet. Still driving the car, although it is not running 100%. Am wondering what the parts will be, and will be asking more questions when they arrive. They will keep the car for a few days for some kind of rebuild. Will post more notes at the end of next week, once the work is completed. Dealership doing a great job so far and the car is still under warranty.
Sounds like you may be about to encounter the CBU experience. Needless, you might want to seriously consider an extended warranty policy. Just make sure the policy doesn't exclude CBU repairs.
 
#52 · (Edited)
Hi,
Received my car today after three weeks at the dealer for the typical
"P02D2 BMW Cylinder 4 Fuel Injector Offset Learning At Min Limit"

This time they cleaned the intake manifold and replaced a sensor.
Don't know what else they did to the DDE/ECU.

The car has 65k miles in it, mostly at 80mph.
I hope to trade/sell it at 95k miles (before the CPO warranty expires).
So the car should not need the intake cleaned again while I own it.

Remains to be seen if this all has any effect on the every 3-5 week SES from a fuel injector.




Frank
 
#53 ·
I was able to drive the car about 200 miles after receiving it back from the dealer (they had it for 3 weeks)
Received this SES code today:
P02D2 BMW Cylinder 4 Fuel Injector Offset Learning At Min Limit

65025 miles

Not sure it makes sense to have a car that does not operate long enough w/o SES for me to actually drive it.
Guess I should just buy a toll-road transponder for the loaner vehicle, as I drive it more than the 335d!
 
#54 ·
how many of those same injector codes have you had now? Seems like youre probably heading down the same road as others who end up with DDE replacement. Maybe people need to start telling the dealership that you thought you might have seen smoke coming from the DDE area under the hood (passenger side near the windshield) when they get these recurring injector faults since the dealers seem to be forced to blame the first 10 on injectors before finally throwing out the DDE.
 
#55 ·
I had hope that changing the DDE would help - it made no difference at all in my particular car!
Same SES codes before DDE and after DDE.

They might try a third DDE, indicating to me that they actually have no idea what to do, but can't admit.
 
#58 ·
Carbon buildup 335d

I have a 2010 335d. At 60k I had to have the entire top of the engine replaced ( I have had the car since new and it was maintained at the dealer) due to carbon build up. It took the dealer almost 4 months to repair. I am now at 108k and I have to have the a EGR cooler replaced. Almost $1300.00. The car has been maintained and I drive it cautiously. These are the only two issues I have had with car in 41/2 years and 108k. Mostly highway. Just expect to have to pay for these repairs.
 
#59 ·
I have a 2010 335d. At 60k I had to have the entire top of the engine replaced ( I have had the car since new and it was maintained at the dealer) due to carbon build up. It took the dealer almost 4 months to repair. I am now at 108k and I have to have the a EGR cooler replaced. Almost $1300.00. The car has been maintained and I drive it cautiously. These are the only two issues I have had with car in 41/2 years and 108k. Mostly highway. Just expect to have to pay for these repairs.
I guess no extended warranty? I'm glad I pulled the trigger before I hit 50k.

So if you are now at 108k you may be looking at another top end cleaning, no? Maybe now they can just do the Walnut Shell cleaning as per SIB.

Mine is a 2010 and I'm at about 72k. I think I may have some symptons but nothing drastic is happening yet. MPG appeared to be below normal but it is possibly due to heavier than normal traffic, maybe. I'm expecting a major code to be thrown but nothing significant so far.
 
#60 ·
Actually I had the extended warranty after 50k. Good job I had because the repair bill was over$15k (I paid$1000.00 and bmw picked up the rest ). I am over 100k now so no warranty. I now have this EgR problem. I highly recommend the extended warranty even if it is after market type.
 
#63 · (Edited)
BMW's SIB 11 03 14 covers the CBU cleaning and explicitly states it's covered by the BMW factory and CPO warranties.

Quote from the SIB: "WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle/SAV Limited Warranty or the BMW Certified Pre-Owned Program."

I don't think anybody on here has had a verified case of CBU that wasn't eventually accompanied by the SES light and associated fault codes that the SIB requires. Plenty of people worrying about it, or thinking they might have it, but too much worrying makes you paranoid and you start seeing aliens in your closet.

I was on the Ford Superduty forums in 2000 when "cackle" was the big issue and "every Ford 7.3L Powerstroke was doomed to premature failure" by the doomsayers. 14 years later mine, and virtually every other 7.3L powerstroke built that year and since, are still on the road and running strong.

I was on the VW TDI forums in 2010 when all the doomsayers were condemning every Bluetec TDI to certain premature death from HPFP failures. 120K accumulated miles later (for me) with no issues, and every person I personally know with one is still on the road.

Here, now, it's CBU. Every US 335d is doomed to premature failure from CBU. Will mine get it? Maybe, probably, I don't know. If I do up until 100K I'm covered by the BMW warranties. After that, maybe I'll do the EGR delete/catch can/ meth route, maybe I won't. There's a known fix out there if I get it, and even if it's on my dime it's more reasonable than the $14K horror stories from the TDI forum's HPFP failures.

Drive more, worry less. :bigpimp:
 

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#64 ·
BMW's SIB 11 03 14 covers the CBU cleaning and explicitly states it's covered by the BMW factory and CPO warranties.

Quote from the SIB: "WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle/SAV Limited Warranty or the BMW Certified Pre-Owned Program."

I don't think anybody on here has had a verified case of CBU that wasn't eventually accompanied by the SES light and associated fault codes that the SIB requires. Plenty of people worrying about it, or thinking they might have it, but too much worrying makes you paranoid and you start seeing aliens in your closet.

I was on the Ford Superduty forums in 2000 when "cackle" was the big issue and "every Ford 7.3L Powerstroke was doomed to premature failure" by the doomsayers. 14 years later mine, and virtually every other 7.3L powerstroke built that year and since, are still on the road and running strong.

I was on the VW TDI forums in 2010 when all the doomsayers were condemning very Bluetec TDI to certain premature death from HPFP failures. 120K accumulated miles later (for me) with no issues, and every person I personally know with one is still on the road.

Here, now, it's CBU. Every US 335d is doomed to premature failure from CBU. Will mine get it? Maybe, probably, I don't know. If I do up until 100K I'm covered by the BMW warranties. After that, maybe I'll do the EGR delete/catch can/ meth route, maybe I won't. There's a known fix out there if I get it, and even if it's on my dime it's more reasonable than the $14K horror stories from the TDI forum's HPFP failures.

Drive more, worry less. :bigpimp:
Well said. Thanks.
 
#65 ·
Ugh ... just got my first major code -- an engine malfunction light came on tonight, the big icon on the dash. Here's what I was doing. Every so often I give it the boot. Well, on my way home, there's this steep on ramp onto the highway about 1/4 mile long or so where I like to floor it and put considerable load on the engine. There were a couple of cars in front, so I drove really slowly (no one behind me) until they were near the top, then I floored it. Got to about 85 mph or so and the revs were right near 5000rpm, then the light came on. Slowed down to about 70 and cruised home (about 12 miles). Got home, went to the pool. Drank beer. Maybe it will go away. Else off to my mechanic on Monday.
 

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#66 ·
My theory for why I needed NOx sensors and 2 new catalytic converters is that I had not been doing that maneuver, flooring it briskly so that it downshifts and powers on, until the time right before this happened. The theory is that too much CBU came through and lodged itself in the converters overloading and "frying" them. Don't know if the additive I used contributed: a bottle of Sta-Bil for diesels that Walmart had on red dot sale, in the proper dosage of course.

PL
 
#68 · (Edited)
Started car this morning and light is gone. I don't know if it will come back, but I don't want to worry that something bad is going to happen if I push the car. I mean, what's the point of having the ultimate driving machine, then? Might as well drive a Subaru Outback. I'll probably take it in on Mon to have it checked out. Incidentally, this is the first time I filled up with bp diesel and no additive.
 
#73 ·
I've experienced the same power loss and "Engine Malfunction Reduced Power" message on my 2010 X5d. I pulled the same P02CB code as well as code P2621 which is "Throttle Position Output Circuit Low". I've reset the codes a few times but they seem to keep coming back. Anyone know if these codes are related? A number of things I've been reading seem to point to the Throttle Position Sensor and mention testing the voltage to and from the TPS.
 
#72 · (Edited)
My mechanic could not find anything wrong with my car (no leaks, valve issues, excessive carbon buildup, etc). His theory is that maybe the EGR valve closed a bit too slowly given the fuel / boost request but still closed within spec so no egr code got thrown. Maybe some buildup in the egr. Could also be my tune but I haven't had this issue when flooring it before, and I have it set halfway, currently at 5 (I sometimes get injector qty codes if I go beyond 6 out of a 0 to 9 pot).
 
#74 ·
Well, my engine malfunction light came back on and with a vengeance. This time I was 200 miles from home, and the car went into limp mode. I don't know if you've ever driven a heavy diesel car with no turbos, but let me tell you, it's not a good day. I limped 200 miles back home like a slug.

But I made it, and got it to my mechanic. All signs point to stuck egr valve. So I am having it removed and probably replaced. Thought about removing it and cleaning it myself, but don't have the time and I need the car for a weekend trip. Besides, there seems to be a heavy buildup on the egr, which means there is probably cbu in my intake and on my injectors. I am amazed because I had induction service performed not 20k miles ago. The buildup happens fast. My service advisor told me that they are seeing more and more cars with cbu. So now this is starting to happen to the X5s. Mine is at 76k miles. I started to see a drop in mpg and shorter regen cycles. I thought it was because it was very hot and humid here and I'm using the a/c, but maybe not. Maybe it's the cheap fuel I use. I've been using additive and giving it a good boot once a week, but I'm not sure any of that matters. Maybe it's something else.

Well, I gotta determine the extent of the buildup and risk to an injector going. What I've got to figure out is, if it's going to cost me more than a certain amount for repairs, or some annual amount greater than $X, than I may trade the thing in for a 328d wagon. With the much better mpg, and the amount of driving I do, ~20k per year, I may come out ahead.
 
#76 ·
I had to have the top half of my engine replaced around 68k miles ( for carbon build up). I had a bitch fest with BMW and they covered the bill with a$1000.00 deductible. My car was in the shop for almost 4 months and the repair was alost $16k. I put 68k on my car in 26 months so my 2010 335d was one of the first to have this issue. ( car has only been serviced at a BMW service center).. I had to have the EGR cooler replaced at 105k for around $1200.00. I love my car but it does require some high priced fixes. I am just crossing my fingers at this point.
Only spend the money if you want to keep your car for a long time.
 
#77 · (Edited)
Update: The new egr cleared all codes except for one. I'll post a pic of the fouled up one when I pick up my car. The boost pressure sensor was all fouled up with carbon and could not be cleaned to where it would work (the remaining code), so it needs to be replaced. The intake is not bad, probably some buildup on the rings, but he'll add a bottle of BG MOA when he does the oil change, and some BG 244 in the fuel tank every six months. Also, no more off brand diesel for me. And we'll see how it looks in another year, or 20k miles.
 
#84 ·
My 2011 335d was a dealer's "Executive" car with just over 5k miles when I bought it in early 2012. Since then I have kept meticulous data on fuel/miles including correction for odometer error. With just over 47k miles its overall average mpg is 37+. On the last 2k mile trip it averaged over 40 mpg. On the last leg of this trip the SES light came on and I dreaded the much discussed carbon build up and injector problems but was glad it came on within the warranty period.
The code indicated a bad injector and the dealer had one expedited over night. The next day I was told that while the injector was being installed the service technician thought he should also check for the carbon problem. Much to my relief the tech did not find significant carbon and was himself surprised at how little there was. I was also impressed with how knowledgeable and genuinely interested the tech was with diesels so I trust his judgement.
Having said that I'm hoping my experience might provide some clues as to why other cars have, or have not had, the carbon issue.
First, my driving is largely long trips, few under 20 miles with the average being something well beyond 100. I try to "go with the flow" which usually equates to 5 mph over and beyond. I generally use hypermiling driving techniques but don't hesitated to enjoy the torque when appropriate. What might be noteworthy is that the EGR valve update and DDE reprogramming was applied early on which I'm hoping prevented, and will continue to prevent, the carbon build-up. I am careful where I buy fuel and have used BP, Shell, Mobil, Sunoco, and lately premium fuels from Kwik Trip and Cenex.
My hope is that if there are other injectors on their way out they die between now and when it hits 50k miles when the warranty ends.
 
#85 · (Edited)
Thanks for the info. My theory is that given proper updates of the DDE and EGR, and "top tier brand" fuel, CBU will be minimized. Extended warranty plans are $3000 and up for my car currently which doesn't seem like a good enough gamble to pay that much. I take good care of my cars and have had no significant trouble in now my 4th direct injection diesel, 160,000 95,000 260,000 and now 49,000 miles with no CBU problems. I don't believe in using additives due to the lack of data on preventive effectiveness and the idea that diesel fuel varies from refiner to refiner, season, etc. and needs customized additive by the fuel supplier to create all of the necessary qualities for proper combustion.

Best.

PL
 
#87 ·
Out of curiosity, how many 'festers with injector failures have been supplementing the lubricity of their fuel? By supplementing, I mean either running a biodiesel blend or using an additive that improves the lubricity of the ULSD fuel.
 
#89 ·
So far, I had a total of 16 injectors replacement. I had a case of injectors were replaced only 10 miles after just having an injector replacement, happen from driving from the dealer to home. The injectors always failing are #2 and #4. Every attempt at replacing a single injector end up at the SES light turning ON shortly after. It end up at the dealer replacing all 6 injectors.

I do not buy the theory that the problem is the fuel or additive, the same fuel feed all 6 injectors. Replacing a single injectors does not seems to work. The dealer end up replacing all the injectors, recalibrating the ECU and indexing (??) the injectors.
 
#88 · (Edited)
The only two symptoms I noted with the injection failure, other than the SES light, was a slight stumbling during gentle acceleration at low speeds as in a crawling, stop and go traffic jam, and later, momentary rough idle just after starting up, at both cold and hot starts. At cruising speeds things seemed smooth, and my fuel mileage did not seem to vary, 39+. I also tried the Italian tune up and noticed no obvious roughness or reduction in power (a dubious test considering the ample torque). I still have almost 3k miles to let the other injectors die, etc., until I will need to decide to extend the warranty. I'm cautiously pleased with the report of little carbon. I'm planning a long 3k mile in February and project going past the 50k mile mark during the trip. I'm working on plotting the BMW service centers along the trip, just in case.
 
#97 ·
I read a lot about CBU and have become sort of numb about it now. I'll just allocate money to do it and view it as a service item. If it doesn't happen, I'll be that much more ahead. Not going to beat myself up worrying about something I really can't control.
 
#99 ·
Gator - There are numerous posts on this board and other BMW boards that claim with a proper amount of bitching and moaning, and with some help from your SA, you can get BMWNA to cover the CBU cleaning even on cars that are just out of warranty. Seems that it is worth a try, especially since you are the original owner.
 
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