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      01-08-2019, 05:23 PM   #45
h0tp0t
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i have the same problem with my 2017 330i wagon. first noticed the knocking sound at 1/4 tank. was told by the dealer it is a known problem that happens when fuel is low and bmw has no fix yet. now i hear the knocks when its over 1/2 a tank.
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      01-08-2019, 06:24 PM   #46
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I've been reading this thread. Very interested. Will be monitoring it. Very strange to say the least.
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      01-08-2019, 08:44 PM   #47
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My first post here, and I have the same knocking sound on my F36. I notice it closer to 1/8 to empty and I can get rid of the sound by simple opening the gas cap. I believe the fuel pump is partially submerged under fuel at 1/8 and the noise is amplified. But once I pop the gas lid, it releases the pressure and the knocking sound instantly disappears
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      01-08-2019, 10:23 PM   #48
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don't have the issue currently on my 2016
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      01-08-2019, 10:33 PM   #49
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Quote:
Originally Posted by cruisn76 View Post
My first post here, and I have the same knocking sound on my F36. I notice it closer to 1/8 to empty and I can get rid of the sound by simple opening the gas cap. I believe the fuel pump is partially submerged under fuel at 1/8 and the noise is amplified. But once I pop the gas lid, it releases the pressure and the knocking sound instantly disappears
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Originally Posted by cruisn76 View Post
My first post here, and I have the same knocking sound on my F36. I notice it closer to 1/8 to empty and I can get rid of the sound by simple opening the gas cap. I believe the fuel pump is partially submerged under fuel at 1/8 and the noise is amplified. But once I pop the gas lid, it releases the pressure and the knocking sound instantly disappears
Wow! I totally forgot about this thread and am glad that folks are chiming in again.

You are actually pretty correct about the cause of the issue. I had my first oil change with my dealer a few months back and mentioned this issue and the shop foreman was very upfront and told me basically that it had to do with the fuel pump venting system so it is an emissions related issue. BMW is fully aware of this issue and has no fix as of a few months ago but they thought that they could update the software eventually which would "pulse" the venting at such a rate that it would essentially mask the noise. So yes. It was indeed a design flaw that should have been caught. My 2015 335ix didn't have this issue so they somehow "engineered" it in due to poor testing.

Like some here, I can hear it below 1/8 tank full. It can start as early as 1/2 tank as well but only for a short while if I brake hard and the gas sloshes around and causes the fuel pump to not be fully submerged. But I will honestly say that the noise is of a lower intensity now vs when i first picked up my car.

So it's a wait and see game. I filled out one of their BMW post service surveys and told them that they need to find a fix soon in their "what would you like BMW to know" section. I will definitely post an update if I hear of anything. I will mention this again this year when I go in for my 2nd service.
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      01-21-2019, 03:11 PM   #50
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This is very interesting. I have a 2019 440i Gran Coupe. Same exact issue. I only notice the noise when the talk is nearly empty. The theories about fuel pump resonance in an empty tank make sense to me. Thought I was going crazy because the noise is not related to engine RPM as most rattles are. This should really get on BMWs radar for a fix.
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      01-22-2019, 08:37 AM   #51
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I've never heard this and I always run my tanks pretty low. I think I would have noticed it after 10k Miles of full tanks but I guess not.
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      02-07-2019, 08:27 PM   #52
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Exactly the same noise on my 2017 X1 xdrive28i. But I hear the sound when tank s full or almost full.
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      02-08-2019, 07:35 PM   #53
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2018 340 and I have never heard this.
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      05-17-2019, 02:08 PM   #54
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FIXED

took it to crevier bmw 1/19 again and nothing was done again. i was told by the service rep the knocking/tapping/helicopter sound is normal. i told him bullshit no cars should sound like this especially a bmw. he then admit that it is a known issue for certain models and bmw has no fix. i wont be going back there again.

last week i took it to irvine bmw for service and ask them to look into the knocking/tapping/helicopter sound and i believe the problem is fixed. i havent heard it since.
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      05-17-2019, 05:10 PM   #55
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Quote:
Originally Posted by h0tp0t View Post
took it to crevier bmw 1/19 again and nothing was done again. i was told by the service rep the knocking/tapping/helicopter sound is normal. i told him bullshit no cars should sound like this especially a bmw. he then admit that it is a known issue for certain models and bmw has no fix. i wont be going back there again.

last week i took it to irvine bmw for service and ask them to look into the knocking/tapping/helicopter sound and i believe the problem is fixed. i havent heard it since.
That is the fix for it.

Name:  Screen Shot 2019-05-17 at 6.09.10 PM.png
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Size:  26.0 KB
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      05-17-2019, 11:14 PM   #56
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Quote:
Originally Posted by h0tp0t View Post
took it to crevier bmw 1/19 again and nothing was done again. i was told by the service rep the knocking/tapping/helicopter sound is normal. i told him bullshit no cars should sound like this especially a bmw. he then admit that it is a known issue for certain models and bmw has no fix. i wont be going back there again.

last week i took it to irvine bmw for service and ask them to look into the knocking/tapping/helicopter sound and i believe the problem is fixed. i havent heard it since.
THANK YOU! I am the OP of this thread.

I was at my dealer a month ago and the shop foreman told me they still had no fix but did mention it should be a software fix. So now it looks like I will be making another appointment to get the software update.

I will post once I have been to the dealer.
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      05-17-2019, 11:22 PM   #57
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Quote:
Originally Posted by TheBingoBalls View Post
That is the fix for it.

Attachment 2056083
It appears you can see the whole service bulletin. Can you post the actual SIB if you have access to it? I cant seem to find it myself. Thank you!
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      01-03-2020, 02:14 PM   #58
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So the vent valve failed and changing it fixed the problem. What's the final word. Also is this a Technical Directive? Recall?
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      01-07-2020, 11:04 PM   #59
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Same thing with my 2019 430i. Happens about 50 miles until empty, or sometimes just randomly. Wondering if anybody else had any luck?
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      02-13-2020, 02:44 AM   #60
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Sib 12 20 19 fixed it!!!👍🏻

Following h0tp0t's great post with his service writeup, I went to my dealer and showed him the SIB. The foreman had no idea and initially said that there was no fix from BMW. He agreed to have the tech look into it and they ended up doing the firmware update and now it's fixed.

As I am the OP of this thread from back in 2017, I have a new video of how my car sounds now both inside and outside after i ran down to below 1/8 tank of fuel exactly as my original video from back in 2017.

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      06-16-2020, 08:05 AM   #61
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I just bought a cpo 17 330 and heard the same noise around 1/4 tank. I thought was just me hearing things lol. Still new to the car I figured it was normal but the noise went away after I filled up. Should I bring it back to have it looked at? Ive only had the car for 3 weeks
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      08-06-2020, 02:25 PM   #62
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2017 X1 28I same issue

Having the same thumping sound on my 2017 X1 28I but only after I fill the gas tank. Brought it to BMW and they did the software update but the noise is still there. Makes me think that they still haven't "solved" the issue or it's only temporary.
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      06-24-2021, 05:27 PM   #63
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Quote:
Originally Posted by dsc888 View Post
THANK YOU! I am the OP of this thread.

I was at my dealer a month ago and the shop foreman told me they still had no fix but did mention it should be a software fix. So now it looks like I will be making another appointment to get the software update.

I will post once I have been to the dealer.
So was it a software fix or does the valve need to be replaced? I don't understand how software would fix this. I've got the same issue in my 2018 330i
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      07-25-2021, 05:31 PM   #64
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Quote:
Originally Posted by dsc888 View Post
Hi Guys,

I picked up my new 2017 340ix 2 weeks ago and it's making a knocking noise from the undercarriage when the fuel tank is below 1/4 full. (I know that most people don't recommend running with so little gas in the tank but there are times when I am not near a gas station.)

I noticed there are NO drivability issues. No Check Engine lights. Engine RPMs are stable. I hear it while stopped in Drive or when the car is in Park. I can hear it slightly as I am coasting very slowly also. So it's NOT the drivetrain. It's clearly from the exhaust or the cats. Here's my a video that I shot of the noise.



As I googled this issue, I also found another 340i that had the same issue. Another viewer of this video also chimed in and said his car had the same issue and the dealer said it's related to the cats "cooling off". The poster said that his noise also occurred with the tank below 1/4 tank as well.



Does anyone here have this issue? If so, did you ever get it resolved?
OMG - this is the exact noise my g20 330i makes!!!!!!!!!

Can't believe I found it someone else with it.
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      07-25-2021, 05:45 PM   #65
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Quote:
Originally Posted by JB_AZ View Post
Quote:
Originally Posted by dsc888 View Post
THANK YOU! I am the OP of this thread.

I was at my dealer a month ago and the shop foreman told me they still had no fix but did mention it should be a software fix. So now it looks like I will be making another appointment to get the software update.

I will post once I have been to the dealer.
So was it a software fix or does the valve need to be replaced? I don't understand how software would fix this. I've got the same issue in my 2018 330i
I'm so sorry for the late reply. I've sold my 340ix and have not been here much lately. For those who are wondering, here is a reference back to the software fix. After my firmware flash, the noise was gone for good!

https://www.bimmerpost.com/forums/sh...php?p=25802420
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      07-25-2021, 06:24 PM   #66
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Quote:
Originally Posted by dsc888 View Post
I'm so sorry for the late reply. I've sold my 340ix and have not been here much lately. For those who are wondering, here is a reference back to the software fix. After my firmware flash, the noise was gone for good!

https://www.bimmerpost.com/forums/sh...php?p=25802420
It looks like they have not solved this in the G20 because that is the EXACT NOISE my 330i makes. FFS

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