Need help identifying a sound

bkchang79 · 05-14-2015, 11:57 AM

I have a 2012 128i and I've been noticing a noise whenever I lift off the gas pedal. It happens only when the car is in motion and in gear (reving the engine in park does not produce the sound). I believe the sound is coming from the rear trunk area and it reminds me of a Turbo blow off valve or if you ever use a soft drink fountain machine, that pssst noise when it dispenses the soda.

Its really driving me nuts especially when there's LA traffic! Please help!

Sound Clip

https://www.youtube.com/watch?v=27Cr...ature=youtu.be

mike@x-ph.com · 05-14-2015, 01:42 PM

DO you have a video so we get a better idea of what that sound is?

MightyMouseTech · 05-14-2015, 01:54 PM

Have you disconnected your exhaust flapper valve hose?

bkchang79 · 05-15-2015, 02:37 PM

Quote:

Originally Posted by mike@x-ph.com

DO you have a video so we get a better idea of what that sound is?

https://www.youtube.com/watch?v=27Cr...ature=youtu.be

bkchang79 · 05-15-2015, 02:39 PM

Quote:

Originally Posted by MightyMouseTech

Have you disconnected your exhaust flapper valve hose?

Haven't touched the flapper valve, don't even know where that is located

edisapimp · 05-15-2015, 03:24 PM

head gasket

bkchang79 · 05-19-2015, 12:02 PM

Quote:

Originally Posted by edisapimp

head gasket

Checked the oil and its not milky or overheating

bkchang79 · 05-20-2015, 02:31 PM

Anyone?

edisapimp · 05-20-2015, 02:46 PM

Quote:

Originally Posted by bkchang79

Checked the oil and its not milky or overheating

Sorry - I was joking. I didn't even watch the video ;[

Huecifer · 05-22-2015, 04:00 PM

i posted about this when I first got the car, too, and no one could help me. I also thought it sounded like a really faint turbo blow off valve coming from behind me to the left. No one at any dealership has ever heard it, and it's too faint for anything to pick up on a recording. The only thing I can think of is may it's the seatbelt pre-tenisoner motor working. I've got almost 80k on the car and it hasn't caused any issues, so I've just learned to live with it :/

MightyMouseTech · 05-22-2015, 04:19 PM

Do the 128's have a vacuum operated valve on the muffler?

If they do, sounds like the vacuum line has just popped off.

bkchang79 · 05-27-2015, 05:44 PM

Quote:

Originally Posted by MightyMouseTech

Do the 128's have a vacuum operated valve on the muffler?

If they do, sounds like the vacuum line has just popped off.

I'm going to take it to the dealer, i'll let you guys know what I find

Slow128i · 05-27-2015, 09:05 PM

Quote:

Originally Posted by bkchang79

I'm going to take it to the dealer, i'll let you guys know what I find

Do not take my word 100% but i have the same sound and i believe thats its just the exhaust flap... happens 1st/2nd gear mainly and is heard best when driving in an alley or with a barrier to your side. I havent done a thing and everything runs fine. Hope this helps

05-14-2015, 11:57 AM	#1
bkchang79 Private 3 Rep 74 Posts Drives: 2011 Jet Black e92 m3 DCT Join Date: May 2011 Location: OC iTrader: (2)	Need help identifying a sound I have a 2012 128i and I've been noticing a noise whenever I lift off the gas pedal. It happens only when the car is in motion and in gear (reving the engine in park does not produce the sound). I believe the sound is coming from the rear trunk area and it reminds me of a Turbo blow off valve or if you ever use a soft drink fountain machine, that pssst noise when it dispenses the soda. Its really driving me nuts especially when there's LA traffic! Please help! Sound Clip https://www.youtube.com/watch?v=27Cr...ature=youtu.be Last edited by bkchang79; 05-15-2015 at 02:38 PM..
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05-14-2015, 01:42 PM	#2
mike@x-ph.com Joint Chiefs of Staff 24166 Rep 190,725 Posts Drives: 07-335/12-328/18-M4/21-M4CP Join Date: Sep 2013 Location: Las Vegas iTrader: (23)	DO you have a video so we get a better idea of what that sound is? __________________ Check out our current sale by clicking on this link! https://x-ph.com/sale/ Phone number 702-494-9435
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05-14-2015, 01:54 PM	#3
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Have you disconnected your exhaust flapper valve hose?
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05-15-2015, 03:24 PM	#6
edisapimp Civil Rights Activist 115 Rep 949 Posts Drives: E46 Sedan, E88 Vert Join Date: Apr 2013 Location: Long Island iTrader: (0)	head gasket __________________ E88 Crimson Red Vert MSport 6MT - Listing your mods in your signature is lame. BMS DCI/MHD E30 Flash!!/AA Sport FMIC/VRSF CP w Tial BOV/VRSF 3" DPs/550i clutch w SPEC SMFW/Apex EC-7s/Whiteline RSFB/E92 M3 FCAs/Bilstein B12 Pro Kit/VRSF inlets
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05-20-2015, 02:31 PM	#8
bkchang79 Private 3 Rep 74 Posts Drives: 2011 Jet Black e92 m3 DCT Join Date: May 2011 Location: OC iTrader: (2)	Anyone?
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05-22-2015, 04:00 PM	#10
Huecifer Private First Class 11 Rep 198 Posts Drives: 128i Join Date: Mar 2008 Location: Pittsburgh iTrader: (0)	i posted about this when I first got the car, too, and no one could help me. I also thought it sounded like a really faint turbo blow off valve coming from behind me to the left. No one at any dealership has ever heard it, and it's too faint for anything to pick up on a recording. The only thing I can think of is may it's the seatbelt pre-tenisoner motor working. I've got almost 80k on the car and it hasn't caused any issues, so I've just learned to live with it :/
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05-22-2015, 04:19 PM	#11
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Do the 128's have a vacuum operated valve on the muffler? If they do, sounds like the vacuum line has just popped off.
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