2011 135i DCT/service question

[WillS]

Okay, so my DCT has stalled out a few times in stop-and-go. Brought it to BMW Austin to get it looked at, and was told that the codes thrown were due to low-end gas? I've always put 93 octane in, with 91 once in the boonies of Missouri and no other choice. Am I failing to connect the dots on something obvious here, or what's going on?

[cooler2442]

Are you completely stock 100%? Ask them to check for any DME reprogramming updates or anything if the problem is continuing.

[BuddhaPilot]

Seems to be a pretty common problem as there have been several DCT owners on this forum having the same problem. Did they say your car had "recorded" the use of lower octane gas? I'd really like to see proof based on the fact I've seen others claim their service departments are saying that. I seriously doubt all these people are getting gas at places that have been putting the wrong grade in the tanks on purpose or by accident. My family has been in the gas/service station business for over 40 years now and it's never happened at our place of business. It's against federal and state laws to sell gas misrepresented as another grade (up or down). You can't even fill a storage tank with a diffferent grade if has been specifically designated as regular/mid/super. The checks verifying this are very random and occur more often than gas station owners realize since any car filling up may be a state regulator. If it doesn't test correctly for octane level and quantity dispensed, it's a pretty significant fine. Until BMW can show me on paper that our cars can measure the octane in our gas, I just don't believe it.

[WillS]

Yeah. I'm 100% stock. They said the only codes present were lower octane. Like I said, I've only used 93 when it was available, and that at Shell stations. 91 octane once in the boonies, but hardly enough to start throwing multiple codes.

[Pangloss]

The thing is, you don't actually know that you *weren't* using low-end gas. All you know is you used the nozzle marked 93 octane. It's not like you ran a test on the gas to see what it really was. I hear about gas stations cheating customers all the time. Why would we assume that we're not amongst the cheated?

[WillS]

Because it was over 46 codes, and I've only got 13k miles. I find it hard to believe that everyone is cheating.

[BimmerEnthusiast99]

This doesn't sound like a DCT problem/code, can any of the board experts weigh in here on the relationship between codes throwing low octane and DCT issues? Or could it be an N55 issue?

[daixloxbmw]

I have randomly stalled out twice on separate occasions. Both times I was coming to a semi-hard stop. RPMs just dropped below 700 and sputtered for a second and finally died. No codes/lights that I can see. Restarted it and it ran fine afterward.

My car is tuned with Procede and currently at 11k miles. I ALWAYS get 93 octane Shell V-Power when available and have only gotten lesser 91 octane when in the boonies. The two times I stalled out, I was definitely on 93 octane.

[Dackelone]

Most stalling issues with a DCT end up being either a SW issue or a HPFP/injector issue. Or both! Have you asked your dealer IF you car has the latest SW? Any issues starting your car cold?


Btw... its not "low end" fuel. The dealer means to say that you should only buy/use "Top Tier" fuel. Just google Top Tier fuel to find a listing.

[WillS]

gotcha. they're closed today. so, I should ask about the new N55 software. Anything else? It's hard to see the correlation between codes thrown for bad fuel and stalling, you're right.

I just don't know how I could've gotten multiple bad tanks of gas. I can count on one hand the number of times I haven't put Shell in.

[abirmaher]

Originally Posted by WillS

gotcha. they're closed today. so, I should ask about the new N55 software. Anything else? It's hard to see the correlation between codes thrown for bad fuel and stalling, you're right.

I just don't know how I could've gotten multiple bad tanks of gas. I can count on one hand the number of times I haven't put Shell in.

Had the same issue with mine (also a 2011 135 w dct) but once they did a software upgrade a couple of months ago it has never happened again.

[WillS]

They seem to be dragging their heels on that, however, just pointing at the fuel issue. Anything I can say/do to force them to do the N55 update? I don't think I've had any updates done, and bought the car in March '11. I still have the old DTC icon.

[Pangloss]

Originally Posted by WillS

Because it was over 46 codes, and I've only got 13k miles. I find it hard to believe that everyone is cheating.

I assume this was spread out over multiple tanks of gas and that you bought your gas from different stations. If so I don't fault your reasoning.

I don't mean to belabor the obvious, but I've learned not to ignore the obvious around here.

[WillS]

I would sure hope it was spread out, otherwise it seems I might've just put water in the tank.

Anyway, it seems like the dealership just jumped on that as the root cause of the stalling and didn't want to do the update. Anything I can say or do to steer them that direction?

[WillS]

UPDATE:

Dealer said low grade fuel codes could be tripped by

1) low grade fuel
2) carbon buildups on the injectors
3) higher ethanol content in gasoline in the winter, inflating octane numbers and resulting in poorer quality fuel

Does this sound right, and would it account for the roughness/stalling?

[BimmerEnthusiast99]

^#2 sounds like it would be the most viable culprit to me given your story/circumstances.

[Diver]

When a car dealer says it's bad gas, that is a cop out. They have been playing that game since the beginning of time.

[WillS]

Hmm. Alright, well, any ideas on what I should do? It's still running rough...RPM is variable when stopped.

[Pangloss]

Originally Posted by Diver

When a car dealer says it's bad gas, that is a cop out. They have been playing that game since the beginning of time.

Why? They didn't make the car, and they aren't charging me for the service. What's their motivation?

I agree this wasn't the case for WillS, but why do people find it so hard to believe that service stations sometimes cheat their customers by putting 87 in the 93 pump, knowing full well that 98% of the cars out there work the same either way?

[RPM90]

Originally Posted by WillS

UPDATE:

Dealer said low grade fuel codes could be tripped by

1) low grade fuel
2) carbon buildups on the injectors
3) higher ethanol content in gasoline in the winter, inflating octane numbers and resulting in poorer quality fuel

Does this sound right, and would it account for the roughness/stalling?

Ethanol? Really?
First he blames low octane fuel, then says it could the ethanol INCREASING the octane, leading to a "lower quality fuel"? What the....?
This dude needs to do some diagnostic and it sounds like he needs a knowledgeable tech to help him out.

BTW, I don't see how ethanol makes fuel "lower" in quality. It's been used for years in the US, and Europe is using it more and more as well.
The majority of automobiles running in the US are tuned to run just fine on a 10% mix of ethanol. So, it's a non issue especially related to why your 135i is stalling in stop and go driving.
BMW knows quite well that in the US our gasoline can contain up to 10% ethanol and they tune the engines to run on our fuel.

Can there be more than 10% ethanol in the fuel you are using?
It's possible if ALL the gasoline stations you've used are breaking the law in your area. How likely is that? Not very.
Even if there were 15% ethanol, what would really happen?
Your MPG would suffer, but I don't see how that would cause stalling at light load with stop and go driving.

Do you drive most of your miles with under 10-15 minute commutes?
If so, you're probably not doing your engine any favors as you would not be running it long enough for the engine to reach optimal temps to be able to burn off carbon deposits. It's easy to check. Get out to the highway and drive for at least 15 minutes to make sure the engine is nice and hot. At safe speeds, go steady, and then go wide open on the throttle. If you've got some build up you should see some black-ish exhaust as your engine is burning some deposits.

So, what is causing your stalling?
Since we want to go with the most obvious, your tech needs to check to make sure that ALL software, especially the DSG software is updated. I say this because you're not the first DSG drivers to have had this issue. Others who have had this type of stalling have had their software updated and the stalling problem went away.
How obvious is that? Start there.

If that isn't it, there are other things to look at.

[RPM90]

Originally Posted by WillS

Hmm. Alright, well, any ideas on what I should do? It's still running rough...RPM is variable when stopped.

So your RPM isn't steady.
If you put your warmed engine in park, does the idle still vary?
When you're at idle, in park, turn the AC on. Does the idle vary even more?
Or, does it rise a bit and then steady?

If you think you may have water in the fuel, try a bottle of "heet".
It helps remove water.

I think your tech should check on the DCT software.
But, try the heet. Wait until your fuel light comes on, and then fill up with 93 octane from something like a Shell or "high end" brand, just so you see if the places you are fueling at may not filter water properly.

BTW, I use Costco, Speedway, and BP and have never had fuel related problems. I've also used Shell and Sunoco, but rarely.

Anyway, never had fuel related problems.
I'm not convinced about the so called "top tier" fuel brands, imo.
I don't think Speedway rates top tier, at least not with it's Mountain Dew colored gas.

[WillS]

Originally Posted by RPM90

Ethanol? Really?
First he blames low octane fuel, then says it could the ethanol INCREASING the octane, leading to a "lower quality fuel"? What the....?
This dude needs to do some diagnostic and it sounds like he needs a knowledgeable tech to help him out.

BTW, I don't see how ethanol makes fuel "lower" in quality. It's been used for years in the US, and Europe is using it more and more as well.
The majority of automobiles running in the US are tuned to run just fine on a 10% mix of ethanol. So, it's a non issue especially related to why your 135i is stalling in stop and go driving.
BMW knows quite well that in the US our gasoline can contain up to 10% ethanol and they tune the engines to run on our fuel.

Can there be more than 10% ethanol in the fuel you are using?
It's possible if ALL the gasoline stations you've used are breaking the law in your area. How likely is that? Not very.
Even if there were 15% ethanol, what would really happen?
Your MPG would suffer, but I don't see how that would cause stalling at light load with stop and go driving.

Do you drive most of your miles with under 10-15 minute commutes?
If so, you're probably not doing your engine any favors as you would not be running it long enough for the engine to reach optimal temps to be able to burn off carbon deposits. It's easy to check. Get out to the highway and drive for at least 15 minutes to make sure the engine is nice and hot. At safe speeds, go steady, and then go wide open on the throttle. If you've got some build up you should see some black-ish exhaust as your engine is burning some deposits.

So, what is causing your stalling?
Since we want to go with the most obvious, your tech needs to check to make sure that ALL software, especially the DSG software is updated. I say this because you're not the first DSG drivers to have had this issue. Others who have had this type of stalling have had their software updated and the stalling problem went away.
How obvious is that? Start there.

If that isn't it, there are other things to look at.

Yeah, I didn't really know what to think about that, either.

My trips are usually 2-3 miles in town, once or twice a week (I usually just bike) and then 800+ mile trips every three months or so back home.

That's why I called BS on the low-grade fuel, though. I've gotten gas up and down I-35 and unless they're all screwing with me...