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      04-03-2016, 06:43 PM   #1
srcurtis
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Drone / Turbulance type noise / vibration when accelerating at speeds of 60MPH+

Hi

I recently purchased a 2014 760Li and have been experiencing a very odd noise and seemingly light vibration when accelerating at speeds of around 60-75MPH.

Initially I had assumed that it was a wheel balance issue but this failed to resolve the issue.

The noise, which is difficult to describe, is somewhat similar to the 'turbulence' heard when driving at speed with the front window open, but no rear window for the air to pass through. It could also be described as a 'droning' sound.

Further testing proved that the noise is unaffected by cornering, the gear selected or the RPM of the engine. It only occurs when accelerating, and does not occur if 'coasting' or simply driving at these speeds.

My dealer decided to replace the drive-shaft, but this did not resolve the problem. They then switched out all the wheels with ones of the same size from another vehicle. When the problem persisted they raised a ticket and submitted data to the BMW North America Transmission Dept. who determined that the noise is (and I quote) "the consequence of a known problem with the F01/F02 DME(Engine Management) and EGS(Transmission Management) software calibration. Replacement parts will not correct the issue and no additional repairs were recommended."

Upon querying this with the dealer, at my request, they replied to the determination to ask if a fix is being worked on and when it might be available. The reply received, although not expressly saying so, indicates that there is currently no work being undertaken to resolve the issue and that a fix should not be expected.

So, where do I go from here?

Do other F01/F02 drivers experience this issue? Is it a problem known to forum members, or should I be directing the dealer to look at alternative likely causes for the issue?

Are there any independent BMW experts in or around Florida that I should ask to look at the vehicle?

Any help would be much appreciated.

Thanks

Steve
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      04-03-2016, 11:03 PM   #2
dbs600
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Very sorry to hear this, Steve.

Consider contacting orlandobimmer from this thread:

http://www.bimmerfest.com/forums/sho...d.php?t=897345

Good luck and keep us posted!
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      04-05-2016, 04:37 PM   #3
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Any updates?
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      04-13-2016, 05:58 AM   #4
lemetier
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Quote:
Originally Posted by srcurtis
Hi

I recently purchased a 2014 760Li and have been experiencing a very odd noise and seemingly light vibration when accelerating at speeds of around 60-75MPH.

Initially I had assumed that it was a wheel balance issue but this failed to resolve the issue.

The noise, which is difficult to describe, is somewhat similar to the 'turbulence' heard when driving at speed with the front window open, but no rear window for the air to pass through. It could also be described as a 'droning' sound.

Further testing proved that the noise is unaffected by cornering, the gear selected or the RPM of the engine. It only occurs when accelerating, and does not occur if 'coasting' or simply driving at these speeds.

My dealer decided to replace the drive-shaft, but this did not resolve the problem. They then switched out all the wheels with ones of the same size from another vehicle. When the problem persisted they raised a ticket and submitted data to the BMW North America Transmission Dept. who determined that the noise is (and I quote) "the consequence of a known problem with the F01/F02 DME(Engine Management) and EGS(Transmission Management) software calibration. Replacement parts will not correct the issue and no additional repairs were recommended."

Upon querying this with the dealer, at my request, they replied to the determination to ask if a fix is being worked on and when it might be available. The reply received, although not expressly saying so, indicates that there is currently no work being undertaken to resolve the issue and that a fix should not be expected.

So, where do I go from here?

Do other F01/F02 drivers experience this issue? Is it a problem known to forum members, or should I be directing the dealer to look at alternative likely causes for the issue?

Are there any independent BMW experts in or around Florida that I should ask to look at the vehicle?

Any help would be much appreciated.

Thanks

Steve
Where in FL and which Dealership? If you're not comfortable posting, feel free to PM me.

I can think of a few possible causes. Since it's acceleration influenced, a flat spot rear tire or a wheel balance issue that occurs when the harmonic vibrations from the wheel/tire, output shafts, and drive shaft hit the same frequency. I can also imagine a scenario with airflow through the wheel spokes buffeting with Integral Active Steering positioning of the rear wheels.

Your car is basically the same as my Ghost and I do not have any vibration or buffeting sound. I do have that with the ///M5 at 89-104mph and have yet to resolve it. My previous 760Li had several issues including transmission and drive shaft defects.
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      03-13-2017, 07:37 AM   #5
Luigi007
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srcurtis,

Any updates? Were you able to find root cause of the problem? I have identical issue with my 2010 760Li. It's currently at the BMW dealership being investigated. Any feedback will be greatly appreciated.
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      06-26-2019, 11:00 AM   #6
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Same problem here

I am having the exactly the same problem on my 760 Li 2011.

While accelerating around 100 km/h (55 mph) the rumbling/humming noice and vibration is very clear, while coasting in 55 mph it almost disappears completely. At higher speeds I have to press the gas pedal harder in order to get the noice. Coasting in higher speeds = can not hear noice ot feel vibration at all.

The parts I have replaced without solving the problem:

New engine mounts + gearbox mount
New propeller shaft incl 2 x guibo and center bearing
New (used part) final drive
I have used 4 sets of different wheels = problem does not come from wheels or tyres.

Drive shafts are not replaced but they have zero play.
I am 100% sure it has nothing to do with engine or gearbox (also working perfectly)
I have 275/35-20 rear tyres.
In general, the complete drive train of my car was in bad condition when I bought the car. I had a play in the old propeller shaft with a clicking sound, engine mounts were also in bad condition. I think the former owner in Germany used the power a lot in this car...

However, I just discovered that there is a play in the HSR actuator (rear steering). When I try to rock the track rods by hand I can clearly see (and also hear) a play of about 1-2 mm up and down on both sides of the HSR actuator. Also when the tyre is moved by hand i can feel and hear the play.

This means that the mounting points of the track rods possibly could start to vibrate and create noice and vibration in the car?
By pressing the gas pedal the forces on the track rods increases a lot which may explain why the noice comes with acceleration?

Please post answers what you think about my theory and hopefully some of the members in the thread can post if they found the root cause of the problem or if their cars have HSR actuators.

Plaase check enclosed picture with two red circles showing where the play is located. Picture is from below and the front of car is pointing downwards.

Best regards, Tomas
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      09-22-2019, 11:50 AM   #7
Notwise
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This is a very interesting theory - I have the droning/thrumming on acceleration under the same conditions. Replaced much of the same stuff.

I also notice this - when cold, let’s say backing out of the garage in the morning, then turning the wheel to head down my driveway I will get one or two ‘ping/thunks’ that are audible and can be felt through the wheel. I wonder if that is possibly the play in the rear as well.
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      09-22-2019, 03:52 PM   #8
Dalus
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Hi Notwise!

Sometimes I can also hear clicking sounds when parking my car.

Notwise, please check your HRS actuator if you have a play like I have. If this is true, I think we have found what causes the problem. Then both you and I can fix this and get rid of the rumbling noise!

I am very greatful if you can check this.

Br Tomas
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      09-22-2019, 05:58 PM   #9
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Ok - so I will jack up the back of the car and look for:

1. left/right play in the wheels
2. If I detect play, see if it's in the HRS actuator

I will try this on Thursday as I'm traveling for the next few days.

I will also try not to get my hopes up. I was beginning to be resigned to living with it.
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      09-22-2019, 06:32 PM   #10
Notwise
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Boy - I'm really thinking about this. In what circumstances would *any* play be acceptable? Also, is it possible that ECU for the actuator is faulty or misprogrammed?

My logical path is that the actuator is wearing out, causing play, which causes vibration. If this vibration was present when the car was new, no-one would have bought it like that.

And - I'd rather have a vibration free ride than the rear wheel steering! I wonder, if it turns out to be the culprit, whether one could 'lock' the actuator so there would be no play in it..

And - I wonder, did you test for play with the motor running or off? It's possible that the actuator energizes when the car is running.

Last edited by Notwise; 09-22-2019 at 07:19 PM..
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      09-23-2019, 02:40 AM   #11
Dalus
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Hi,

Yes, my theory is also that the actuator is worn.

It is much harder to feel the play in the actuator when you put the car on jacks and try to rock the tires. You have to be 2 persons to check it this way. The car on jacks, one person rocking the tire and one person under the car feeling the play in the actuator with the hand.

Better is to be under the car when the car is resting on the tires with the suspension in normal height. Just put the car on ramps (or wooden blocks) a little higher than normal just enough to be able to get under the rear from back. Grab where the track rod is fixed to the actuator and rock it hard up and down (not "in and out" from the actuator). My play is inside the rubber "hose".

I have not checked the play with the engine running.

I think that if the ECU is faulty , then you would have a car not running straight when the steering wheel is 12 o'clock (misalignment). Or the rear steering would be locked in position zero all the time. I do not think the rumbling comes from a faulty ECU, it has to be mechanical.

The play is not "inside" the actuator where the steering motor is forcing the actuator back and forth. The play is in "bearings" of the connectors that . If you rock the left side connector you do not feel any movement in the right side connector. This means that if I "lock" the actuator in zero position, the problem will still be there. This means also that the tires do not turn that much because of the play in the actuator (since it is not in the direction "in-out" of the actuator).

The actuator in 760 is the same for all F01/F02 including 730 diesel with less than half of the power. Maybe the actuator is too weak to handle the power in 760? Part no is 33346776294, you find used actuators on ebay.
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      09-23-2019, 06:07 AM   #12
Notwise
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I saw the used ones on eBay - of course, the first thing I think about is that the used ones are worn too!

I’m looking forward to trying this and reporting back.
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      09-23-2019, 07:16 AM   #13
Notwise
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Here’s a related link on issues with rear steering:

https://www.bimmerfest.com/forums/sh.../topics/640659
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      09-26-2019, 10:01 AM   #14
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Ok, I set up my phone video recorder to look at the HRS actuator - I then started the car and whilst in park I turned the wheel several times, lock to lock. I then put the car in drive and repeated. To my great surprise, the actuator did not turn at all! Is the active steering only 'active' when the car is in motion?
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      09-26-2019, 11:04 AM   #15
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To be able to see when the rear wheels are turning you can drive the car (on a big open parking spece) and roll down the window and turn the car and look back on the rear wheel at the same time. When the car is parked the rear wheels are always in zero position, even if enigne is running.
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      10-09-2019, 06:23 AM   #16
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Ok - I had the dealer test the HRS actuator for play, function, everything. Mine operates normally. So, that's not it. Bummer.
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      10-09-2019, 08:14 AM   #17
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Sorry to hear that they did not find the cause of the problem.

Did they also check for play in other parts of the multi link rear axle that could cause the vibrations?
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      10-11-2019, 11:36 AM   #18
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Turbulance noise on acceleration!

Hi Peeps...Mine has started doing this after New engine replacement. I don't know if it is related. New Guibos...center bearing and Coils and plugs. Getting worse everyday!!!
Has anyone found a solution?
Thanks,
Raf.
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      10-14-2019, 10:31 AM   #19
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Ok...Update...I am pretty sure it is Torque convertor "Shudder".
I drained a little fliud and added two tubes of Shudder guard...85% improvement. Irony is fluid was changed recently with filter ...But did NOT help!
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