fluttering sound

[N8dawg]

at about half throttle in first and second, there is a mechanical fluttering(best way I can think to explain it). Anyone know if this is a problem or is it normal?

[Ctm309]

Air Filter? There is a noise like you say sometimes from the air filter rattling in the air box. Not uncommon. Then it could also be many things.

[MrHarris]

V8 flutter?

[JIO]

With 10 individual throttle bodies, one or more may be rattling a bit as the air enters. It's probably doing it in all gears, but you can hear it better in the lower gears when the tires aren't drowning out the rattle sound. As long as there is no surging, I wouldn't worry about it. If it continues to bug you (it would bug me but I'm OCD...he he) see if the service people can hear it.

[MrHarris]

I thought their were 8 ITB's?

[Dengel]

Originally Posted by JIO

With 10 individual throttle bodies, one or more may be rattling a bit as the air enters. It's probably doing it in all gears, but you can hear it better in the lower gears when the tires aren't drowning out the rattle sound. As long as there is no surging, I wouldn't worry about it. If it continues to bug you (it would bug me but I'm OCD...he he) see if the service people can hear it.

Hes right. It could be the sound of 2 extra throttle bodies screwing everything up.

[N8dawg]

I have been analyzing the sound and thought I'd be a little more specific. It comes in at about 2100-2400 RPM in all gears(I've at least heard it in the first 4) and it's much louder when the engine is cold. It kind of sounds like a moped engine lives in my car and gives a little rev during those 300 rpms.

[Brosef]

Originally Posted by Dengel

Hes right. It could be the sound of 2 extra throttle bodies screwing everything up.

agreed. that's a common problem with these 8-cylinder M3's.

[spyderco10]

i had a flutter too. it happened after i took my car in for service at bmw. turns out they removed the intake manifold, and when they put it back on, they didn't seat it properly on top of the throttle bodies. there were at least 2 throttle bodies completely exposed to unfiltered air! this and several other incidents at bmw is the reason i have no confidence in their techs. it's not that they're not able to do good work. oh yes they can. but it's all about money. the more cars they work on per day, the more money they make. so they don't give a rip about the quality of work they do. sad but true.

[Radiation Joe]

Originally Posted by spyderco10

i had a flutter too. it happened after i took my car in for service at bmw. turns out they removed the intake manifold, and when they put it back on, they didn't seat it properly on top of the throttle bodies. there were at least 2 throttle bodies completely exposed to unfiltered air! this and several other incidents at bmw is the reason i have no confidence in their techs. it's not that they're not able to do good work. oh yes they can. but it's all about money. the more cars they work on per day, the more money they make. so they don't give a rip about the quality of work they do. sad but true.

I had forgotten about that. Same thing happened to me. Caused an odd sound, like fluttering or rattling.

[KJM3]

Originally Posted by spyderco10

i had a flutter too. it happened after i took my car in for service at bmw. turns out they removed the intake manifold, and when they put it back on, they didn't seat it properly on top of the throttle bodies. there were at least 2 throttle bodies completely exposed to unfiltered air! this and several other incidents at bmw is the reason i have no confidence in their techs. it's not that they're not able to do good work. oh yes they can. but it's all about money. the more cars they work on per day, the more money they make. so they don't give a rip about the quality of work they do. sad but true.

That goes for most dealers these days unfortunately, most of the older good techs have moved on or retired and you have younger guys with zero experience except what they learned in a trade school or watered down factory training. Last generation just havent produced a lot of skilled/experienced auto techs, finding one these days is a challenge.

But anyway, why would they remove the airbox over the throttle bodies for a normal service? Just curious, seems like a lot of work if nothing is wrong under there.

[Radiation Joe]

Originally Posted by KJM3

That goes for most dealers these days unfortunately, most of the older good techs have moved on or retired and you have younger guys with zero experience except what they learned in a trade school or watered down factory training. Last generation just havent produced a lot of skilled/experienced auto techs, finding one these days is a challenge.

But anyway, why would they remove the airbox over the throttle bodies for a normal service? Just curious, seems like a lot of work if nothing is wrong under there.

Mine was off for the idle valve fix.

[KJM3]

Originally Posted by Radiation Joe

Mine was off for the idle valve fix.

Makes sense, it sounded like it was in for a routine service when they removed it and I was just curious.

[spyderco10]

Originally Posted by KJM3

That goes for most dealers these days unfortunately, most of the older good techs have moved on or retired and you have younger guys with zero experience except what they learned in a trade school or watered down factory training. Last generation just havent produced a lot of skilled/experienced auto techs, finding one these days is a challenge.

But anyway, why would they remove the airbox over the throttle bodies for a normal service? Just curious, seems like a lot of work if nothing is wrong under there.

they took mine off to replace the a/c evaporator, which had developed a leak. being that this was a big job because there was major disassembly involved, i was concerned that they wouldn't put it all back together properly. i was right.

the engine cover was so high off of the throttle bodies, it was touching the sway bar, and causing this awful vibrating noise inside the cabin. it took me a while to figure out what the problem was (fluttering upon acceleration and buzzing from the dash). i'm grateful that i'm somewhat mechanical, was able to figure it out, and put everything back together the way it was supposed to be.

[JCtx]

Originally Posted by spyderco10

the engine cover was so high off of the throttle bodies, it was touching the sway bar, and causing this awful vibrating noise inside the cabin.

Really? How many miles on the clock when you noticed this? I ask because your cover was OFF the rear throttle bodies , meaning your engine was ingesting unfiltered air thru that small gap. Probably not a huge deal since the gap is small, but you have to be an idiot not to see it didn't seat properly. Did you get your idle valve replaced? It'd be hard to believe the factory screwed up, but it's always possible. By the way, I removed mine, so I know what I'm talking about (pic below). And no, no need to remove the sway bar for that job.

Finally, I could bet cash money the rubber gaskets were permanently damaged when tech just pushed down on the cover when it obviously 'bit' the gaskets inwards, preventing the cover to sit properly. If I were you, I'd remove the cover and inspect them. Fit is super tight, and you have to be patient AND CAREFUL until all 8 'trumpets' are seated properly. And use a socket, not a screwdriver for the clamps. Take care.

[spyderco10]

no they didn't replace the idle valve, they replaced the a/c evaporator. i too completely removed the engine cover. the gaskets looked okay, but i'm no expert, so they very well may have been damaged. i would say i only put on maybe 300 miles before i figured out the engine cover wasn't seated properly.

and i don't know if my engine cover is defective/crooked or what, but i had a hard time seating it properly too. it just would not sit straight. all 8 "trumpets" would not fit into the throttle bodies tightly. it's like it would rock to the front and the rear, but would not go down flat on all 8 throttle bodies. so i just pushed it down straight as far as I could and tightened the screws. thanks for the tips though.

[Krozi]

Originally Posted by Dengel

Hes right. It could be the sound of 2 extra throttle bodies screwing everything up.

That's some funny shit

[booch]

Originally Posted by elp_jc

Really? How many miles on the clock when you noticed this? I ask because your cover was OFF the rear throttle bodies , meaning your engine was ingesting unfiltered air thru that small gap. Probably not a huge deal since the gap is small, but you have to be an idiot not to see it didn't seat properly. Did you get your idle valve replaced? It'd be hard to believe the factory screwed up, but it's always possible. By the way, I removed mine, so I know what I'm talking about (pic below). And no, no need to remove the sway bar for that job.

Finally, I could bet cash money the rubber gaskets were permanently damaged when tech just pushed down on the cover when it obviously 'bit' the gaskets inwards, preventing the cover to sit properly. If I were you, I'd remove the cover and inspect them. Fit is super tight, and you have to be patient AND CAREFUL until all 8 'trumpets' are seated properly. And use a socket, not a screwdriver for the clamps. Take care.

this is a great pic!

[Thebigbus]

Sorry to resurrect an old thread :-). I test drove a used 2009 e90 dct m3 yesterday...first m3 I've driven.. Noticed a very odd sound, only when accelerating under load. Sounded like crackling/fluttering, almost like air trapped under paper. Seemed like it was more from the front left of the vehicle. I wouldn't say it was a "rattle" as some have described, but more a crackle, or sound like tearing something. Very weird.

I will obviously bring it up when I get the PPI, but just wanted your input as to whether this is the same kind of noise so many are hearing during acceleration. I parked the car and revved the engine, and the sound wasn't there. Only during acceleration was it there. I should've paid attention to e rev range when it happened, but unfortunately I didn't. Car seemed great other an that, and other than the driver side mirror not lining up properly.

Thx for any help! Hopefully will be an m3 owner by the end of January :-)

[Sabir]

Originally Posted by Thebigbus

Sorry to resurrect an old thread :-). I test drove a used 2009 e90 dct m3 yesterday...first m3 I've driven.. Noticed a very odd sound, only when accelerating under load. Sounded like crackling/fluttering, almost like air trapped under paper. Seemed like it was more from the front left of the vehicle. I wouldn't say it was a "rattle" as some have described, but more a crackle, or sound like tearing something. Very weird.

I will obviously bring it up when I get the PPI, but just wanted your input as to whether this is the same kind of noise so many are hearing during acceleration. I parked the car and revved the engine, and the sound wasn't there. Only during acceleration was it there. I should've paid attention to e rev range when it happened, but unfortunately I didn't. Car seemed great other an that, and other than the driver side mirror not lining up properly.

Thx for any help! Hopefully will be an m3 owner by the end of January :-)

Hi mate. Hope you've owned the m3 and many more thereafter. I have heard this sound in my 320d as well it's like a fluttering sound. How did you get this fixed. Kindly educate please.

[Sabir]

Originally Posted by N8dawg

I have been analyzing the sound and thought I'd be a little more specific. It comes in at about 2100-2400 RPM in all gears(I've at least heard it in the first 4) and it's much louder when the engine is cold. It kind of sounds like a moped engine lives in my car and gives a little rev during those 300 rpms.

Hi mate. Sorry to resurrect this old thread. I have a moped engine living in my car and which makes a fluttering sound at 1500 to 2500 rpm. Curious to know what was the issue and how did you manage to remove the moped out of your car.

[kb9uwu]

Wonder if anyone in this thread still owns there ///Ms?