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Discussion Starter #1
Hi guys

Car hasn't been running great recently, idling up and down, jerking when accelerating, seemed down on power. At weekend it gave me following codes

2B47 misfire impairing exhaust cyl 6
2B48 misfire impairing exhaust cyl 7
2B49 misfire impairing exhaust cyl 8
2B4A misfire impairing exhaust cyl 9
2B4B misfire impairing exhaust cyl 10
2B4E misfire impairing exhaust multiple cyl
275D Oxygen sensor limit position error, bank 1
27CB Oxygen sensor restart diagnosis after catalytic converter, bank 2
27AB Oxygen sensor adaptation at limit position before catalytic converter bank2
2B3A misfire with cutoff cyl 6
2B3B misfire with cutoff cyl 7
2B3C misfire with cutoff cyl 8
2B3D misfire with cutoff cyl 9
2B3E misfire with cutoff cyl 10
2B41 misfire with cutoff multiple cyl

Any ideas? Was thinking maybe a bad oxygen sensor? Possible ionic module or fuel pressure regulator?

Any help appreciated! Have been using my partners tt for the past few days as I have had no time to look at my beast and I really need my beast back! Although I do like the dsg transmission!
 

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Looks like you have vacuum leaks allowing the engine to pull in additional air not measured by the MAFs. Take a picture of your intake plenums from chest height standing in front of the car and post it.
 

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Everything looks fine from that picture. I was thinking intake plenum not properly seated.

Just curious, but looking at your recent posts, do you hear a whoosh when opening the gas cap as the vacuum is released?
 

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Discussion Starter #9
Yeah I get a whoosh when opening up the cap.

The car has always had this fault since I got it! I took it to BMW and they said it was a very common code they find but nothing was wrong! I don't have a voltmeter unfortunately!
 

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Yeah I get a whoosh when opening up the cap.

The car has always had this fault since I got it! I took it to BMW and they said it was a very common code they find but nothing was wrong! I don't have a voltmeter unfortunately!
Ok. First off, you need to replace the carbon canister. This acts as the vent line for the gas tank. The DME cycles the tank vent valves periodically at idle to draw fuel vapor off the top of the tank. This places a vacuum on the tank, but the carbon canister is supposed to allow fresh air in to prevent vacuum locking the tank. When the tank is under a vacuum, there is risk of imploding and breaking a seal. On top of that, the vacuum on the tank lowers the net positive suction head seen by the fuel pump(s) reducing their flow. This may have caused some of the previous problems you had with fueling.

Secondly, with the tank under a vacuum, fuel evaporates more readily than at atmospheric pressure. The DME monitors the fuel trims and lambda when operating the tank venting valves. Excessive fuel vapor being pulled in may be triggering the misfires and causing the lambda adaptation errors you are seeing.

Carbon canister is cheap, I would replace that first and see if anything changes. We'll figure out the alternator after that.
 

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Discussion Starter #12
Can the old canister be cleaned and reused? Just asking as I won't get new one until the Monday or Tuesday next week!
 

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Ok part ordered! It's just in behind the dust guard on the right hand side rear isn't it Jim?
Correct. Right side, remove the fender liner completely. Upper rear part of arch, 11 o'clock position.

Don't know about reusing, wouldn't bother with it. You can probably just disconnect the lines from it temporarily.
 

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Discussion Starter #14
Part will be here tomorrow.

Strange thing happened today.

Had to drive the m6 to pick something up as my other half was using her tt. Started the beast and after few seconds engine fault come on and cars sounds rough! Rpm drops to 5k.

Get to my destination and park up. 2minutes later I come out to car and start her and everything is normal! No faults, no warning, engine sounds fine. Drive home without issue. Seems odd?
 

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Discussion Starter #15
Little update.

Last night I decided to swap over the ionic modules as I wait for the new charcoal canister. Got no codes and car is running fine now. No cel or engine fault and is pulling like a train again.

Here's hoping it was a loose connection or something like that.
 

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Discussion Starter #16
Aaaaaarrrrgggghhhhhh!!!!

Spoke too soon. Just started her up and she sounded rough and after about 1min I got these codes again.

Ionic module swap hasn't changed anything.

Please any advice help appreciated. If this is going to turn into a long term replacement of various things then I think I will just get rid of my beast. Have started falling out of love with her after nearly 2 years! :(
 

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When I had a problem similar to yours where I had whoosh sound coming from fuel tank when I took cap of also trying to refuel was a nightmare because the pump would click off every so often and tank wouldn't be full, the problem I had was the two breather values under the penlum either side.
Once these were changed that stopped.

Do you think you have a bad fuel pump or sender as well?

Sent from my SM-N9005 using Tapatalk
 

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Discussion Starter #19
I have no idea what the problem is! Ruled out ionic modules. Charcoal canister will be renewed today or tomorrow but disconnected it last night and the problems persisted. I am going to swap over the pre-cat oxygen sensors to see if that does anything. Don't want to be shelling out thousands to put it right. So doing the cheap or free things at the moment.

My fuel pressure is showing at a steady 4bar so it seems fine. I think! So the fuel pump seems fine.

Really don't know what to do hence why I am on here.

Which valves do you mean?
 

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Try the new canister first. If the tank is allowed to at a vacuum under any condition, running or not, it is a problem.

Next, if problems persist, the tank vent valves are located under the intake plenums attached to the idle actuators. Remove the small tube on both sides and electrical connector, 10mm socket on the bolt and pull it out. Blow through it. If *any* air goes through, it's faulty. Air should only pass when 12V applied to terminals.

They are about $100 each, less of non-OEM.
 
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