[austinla335d]

At my last oil change back at 36k, I complained of decreased fuel economy and occasional hesitation that's hard to predict. No error codes, could not replicate, so nothing.
But now, at 44k, mileage has decreased further. I'm averaging 22mpg per tank, sometimes 25, sometimes 20.
When I told my service advisor it was still an issue and that I don't want to read "tried to replicate but could not", he told me he would have the mechanic call me.

Later that day, the service GM called and basically said his only shot (on my behalf) was to fill up the tank, drive the car on his daily 90 mile commute until the tank ran out, take all of the data on his daily drive including ambient temps and so on, and submit it all to BMW. I wasn't too comfortable with that, primarily because if he put 300-400 miles on my car and then just gave it back to me and said "Sorry, BMW doesn't see an issue" I would be pissed.

So he then offered to allow me to do the same. Exactly what he explained to me, I should do, and then report back with my data and he will submit it. I think he plans to submit it as his own data as well.

I asked if carbon build up could cause terrible fuel economy but no CEL, and he said its possible but he wouldn't know until the intake manifold came off, and he can't so that without BMW.

I'll keep y'all posted.

[DieselRacer]

Yes, keep us posted, please...

[335ddd]

i am in the same boat as you. no CEL.
i only got 37k miles and my fuel economy nothing to cheer about. i also feel that the car should be faster. So I connected the Torque app and my power numbers are pretty low.

i was thinking just going to RSW in NJ and paying for cleaning. much cheaper than dealer even though my car is under warranty i just feel like its going to take months of back and forth to get anywhere.

[skychismo]

How many people have had the carbon cleaning done. I ask because after they did mine under warranty, they've been chasing SES light after SES light, and now it seems as if the ded is fried

[WreckerX5d]

Mine took 2 weeks to get CBU and injectors replaced. That included ordering the parts and waiting a week for that.

[Timujin]

I am at 40k and just ran out a 500 mile tank of fuel. Drove to Vegas and back on 7/8 of a tank with A/C mostly on. On the way to Vegas my average speed was a lot higher than the trip home (as usual). I am taking another trip to OR soon and will strive for max fuel econ on at least one tank to judge CBU.

Good luck.

[austinla335d]

Originally Posted by Timujin

I am at 40k and just ran out a 500 mile tank of fuel. Drove to Vegas and back on 7/8 of a tank with A/C mostly on. On the way to Vegas my average speed was a lot higher than the trip home (as usual). I am taking another trip to OR soon and will strive for max fuel econ on at least one tank to judge CBU.

Good luck.

Interestingly, we went LA to Dallas, then back. We averaged 30.8 mpg on 95% highway with cruise control almost always. Average speed was 54 mph.

A similar style but shorter trip last fall had the display reading 38mpg for hundreds of miles. Something has definitely changed greatly. I really an leaning toward CBU.

[austinla335d]

Originally Posted by Wrecker335d

Mine took 2 weeks to get CBU and injectors replaced. That included ordering the parts and waiting a week for that.

Since my car is running alright, if it worked out I would assume they would order stuff and when it came in, I'd drop the car off and pick up a loaner at that time. Assuming the worst, as in this begins months of battles, I'm going to shoot for a fun loaner. My SA is great and would likely arrange accordingly. As long as it has sport package or is bigger/nicer than what I drive now

[taibanl]

Originally Posted by austinla335d

Interestingly, we went LA to Dallas, then back. We averaged 30.8 mpg on 95% highway with cruise control almost always. Average speed was 54 mph.

A similar style but shorter trip last fall had the display reading 38mpg for hundreds of miles. Something has definitely changed greatly. I really an leaning toward CBU.

I am in a very similar boat with similar suspicions, been slowly declining, now getting 30HWY!

[Jhayd11]

From my very extensive call around the DC metro area, walnut blasting is NOT an option for diesels. Called 3 BMW reps, 7 performance shops that walnut blast gasoline cars, and multiple diesel mechanic shops.

CBU must be machined out. which is why it takes so long and costs so much.

If I am wrong I was forced to sell my 335D for no reason.

[taibanl]

Originally Posted by Jhayd11

From my very extensive call around the DC metro area, walnut blasting is NOT an option for diesels. Called 3 BMW reps, 7 performance shops that walnut blast gasoline cars, and multiple diesel mechanic shops.

CBU must be machined out. which is why it takes so long and costs so much.

If I am wrong I was forced to sell my 335D for no reason.

You must have missed all the posts in april that had the new procedure/parts

[austinla335d]

Originally Posted by Jhayd11

From my very extensive call around the DC metro area, walnut blasting is NOT an option for diesels. Called 3 BMW reps, 7 performance shops that walnut blast gasoline cars, and multiple diesel mechanic shops.

CBU must be machined out. which is why it takes so long and costs so much.

If I am wrong I was forced to sell my 335D for no reason.

From my limited research... My BMW dealer will walnut blast my 335d. It's new news. But yep, they'll clean your carbon for just over $1k... And with the parts the local performance shops do it for $700.

[duramax]

So why are dealers charging $6,000? (from what I read on other posts)

[kbsilver]

Originally Posted by duramax

So why are dealers charging $6,000? (from what I read on other posts)

$6K was the old procedure of pulling the head, sending it out to be cleaned in a machine shop, and replacing the intake manifold, tossing the old one away.

Walnut blasting is done with the head in place, and now just the intake is removed and that is ultrasonically cleaned instead of replaced. So if it's really no more than $1K, to me 1-2 times in the life of the car is acceptable.

Not pulling the head is able to keep all fluid systems intact, and avoids the need of all new head bolts (that's $hundreds alone) as they are not reusable.

[Jhayd11]

kbsilver - you are say "so if it's"...

sounds like you haven't had it done yet. Is this something that anyone has actually had done on a diesel.

[Nushibo]

Originally Posted by Jhayd11

kbsilver - you are say "so if it's"...

sounds like you haven't had it done yet. Is this something that anyone has actually had done on a diesel.

I will let you know tomorrow when i drop my car off for the injector issue. Ill see if I can squeeze the SIB for CBU into the mix.

[F32Fleet]

Originally Posted by duramax

So why are dealers charging $6,000? (from what I read on other posts)

Bitter owners. Even when the SIB was actually posted some members were still crying that it would be thousands of dollars. I said about $1k or less. More than gassers but not much.

Misery loves company


SI B11 03 14.

[Jhayd11]

SOCOM, thanks for the Bulletin reference!

I'll ask my rep, here, what the cost is, as well.

Glad to see you hanging around, as well, as an ex-owner.

[Nushibo]

Dropped my car off today. They are looking at the code and they noted SI B11 03 14. Ill let you know a rough estimate and we can compare by dealership etc. Friend is the mech working on it so ill have info as it rolls in.

[kbsilver]

Originally Posted by Jhayd11

kbsilver - you are say "so if it's"...

sounds like you haven't had it done yet.

That would be correct. I have 49K miles and have yet to see the SES illuminated. This is the longest any BMW I've ever owned without an SES.

[F32Fleet]

Originally Posted by Jhayd11

SOCOM, thanks for the Bulletin reference!

I'll ask my rep, here, what the cost is, as well.

Glad to see you hanging around, as well, as an ex-owner.

NP. I still have my car btw.

[Jhayd11]

Damn you SOCOM! I sold mine when it needed its 3rd CBU cleanup, before they released this SIB. Would have cost me 8k.

my 335i just doesn't compare.