E90Post
 


Studio RSR
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Unsettling N54 Deceleration Sound



Reply
 
Thread Tools Search this Thread
      04-30-2017, 05:01 AM   #1
Holtdahooligan
New Member
United_States
6
Rep
13
Posts

Drives: 2013 BMW X5 35d
Join Date: Aug 2014
Location: Tampa, FL

iTrader: (0)

Unsettling N54 Deceleration Sound

I would like to start off by stating that this is NOT wastegate rattle, the easily diagnosable sound we all know and hate.

So, guys, what is going on with my motor? I took my car to a local indy bimmer shop and even they couldn't figure it out. They removed the valve cover and said everything looked fine. No gold look to the cam ledges, chain was tight and guides in good shape.

This has been going on for about 6 months now. I haven't noticed any decrease in engine performance and haven't gotten a single code. I'm full bolt on with inlets and e60 MHD flash (09 135i MT). My N54 motor currently has 102,500 miles on it.

It sounds like some kind of oil starvation/valve train wine and only happens on deceleration. It doesn't matter whether or not the oils hot or cold. Engine braking from any rpm over about 3k will cause this loud decel noise. No, this isn't wastegate rattle.

This first video is with the windows up and oil up to temp, replicating the sound once.
https://youtu.be/fJgnNP5YgWo

This second video is with the windows down, oil not fully warm and I'm able to replicate the noise twice.
https://youtu.be/KxfKdh-IStQ

Please note that the noise I am referring to is not the BOV purging or turbo spoil sounds. I'm talking about the aggressive chain-like chattering sound as the RPMS fall.

I have attached an oil analysis which did show higher than average levels of Tin and Lead. This analysis was done at 101,256 miles with 2,233 miles on the oil.

I haven't found anything similar to this sound online and could really use some help. Does anyone have a clue what it could be? Thanks for your time!
Attached Images
 
Appreciate 0
      04-30-2017, 05:14 PM   #2
Had0uken!
Private
United Kingdom
21
Rep
71
Posts

Drives: BMW 335i E93 Convertible
Join Date: Sep 2016
Location: Western Yorkshire

iTrader: (1)

Crankshaft?

I'm not a mechanic or engineering minded in any way - I had a metallic clanging/rattle on mine (not wastegate at this point) when letting off throttle/decelerating and occasionally when blipping throttle.

Luckily car was still under warranty - took into Bmw (suspecting wastegate rattle as that was the only rattle info I could find online). Turns out it was the crankshaft - a bearing had spun or something. they didn't know why, put it down to oil starvation or just manufacturing defect. Sorted out under warranty thankfully.


Hopefully it's not that for you, again could be completely off the mark but this is my experience.
Appreciate 0
      04-30-2017, 07:57 PM   #3
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

Is this issue only replicable while driving? Can you not replicate the sound while in park or neutral? I watched both videos and I don't think it's speed related, or RPM related, it seems only related to decel in low load situations (i.e. in gear). Does that seem correct?
Appreciate 0
      05-01-2017, 12:50 AM   #4
Holtdahooligan
New Member
United_States
6
Rep
13
Posts

Drives: 2013 BMW X5 35d
Join Date: Aug 2014
Location: Tampa, FL

iTrader: (0)

Quote:
Originally Posted by dyezak View Post
Is this issue only replicable while driving? Can you not replicate the sound while in park or neutral? I watched both videos and I don't think it's speed related, or RPM related, it seems only related to decel in low load situations (i.e. in gear). Does that seem correct?
You are correct. The sound is only replicable during decel under load (in gear). Indy shop could only replicate the sound when driving the car but not while on a lift. Thank you for reminding me of this.
Appreciate 0
      05-01-2017, 07:35 AM   #5
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

I've never seen/heard anything like that before so I'm just going to throw some ideas out and see what sticks. If this is load related, but definitely with the engine, then that does help narrow things down. I don't think it can be anything with the belt drive or accessories. But it could be the timing chain or tensioning system. It could be the vanos system. Not likely to be valvetrain. Possibly a REALLY bad PCV failure?? Any oil consumption?

Again, I'm not sure, just seeing if anything gets the juices flowing and helps you figure it out.
Appreciate 0
      05-01-2017, 01:04 PM   #6
MysticRob
Captain
MysticRob's Avatar
573
Rep
870
Posts

Drives: 2009 335i E90
Join Date: Jan 2017
Location: Fremont, CA

iTrader: (0)

Garage List
Quote:
Originally Posted by Holtdahooligan View Post
You are correct. The sound is only replicable during decel under load (in gear). Indy shop could only replicate the sound when driving the car but not while on a lift. Thank you for reminding me of this.
If I'm hearing the vids correctly it sounds like an almost metallic, and very rapid, high rpm whine that spools down slowly.

Since you have inlets, I wonder if they are unmasking the sounds of the turbos themselves. With such a fast whine I'm thinking that's what I'm hearing.

Curious if it would still be as audible without the inlets.
__________________
2008 E61 535xi Sport Wagon / 100k Miles / Deep Sea Blue Metallic / Natural Brown Interior / MHD Stage 1 91 CA-Octane Tune.
SOLD - 2009 E90 335i M-Sport Sedan / 143k Miles / Alpine White Exterior / Chestnut Brown Interior / Mishimoto FMIC / xHP Stage 2.
Appreciate 0
      05-01-2017, 02:26 PM   #7
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

Quote:
Originally Posted by MysticRob View Post
If I'm hearing the vids correctly it sounds like an almost metallic, and very rapid, high rpm whine that spools down slowly.

Since you have inlets, I wonder if they are unmasking the sounds of the turbos themselves. With such a fast whine I'm thinking that's what I'm hearing.

Curious if it would still be as audible without the inlets.
I've ran fully open turbos before in single top-side setups with no filter at all and never heard that. But it's possible I guess if the thrust bearing was shot.
Appreciate 0
      05-01-2017, 02:30 PM   #8
austin
Private
24
Rep
80
Posts

Drives: '07 e90 335i
Join Date: Jul 2013
Location: CA

iTrader: (2)

Garage List
2007 e90 335i  [0.00]
Do you have a gopro that you can mount somewhere else on the car in hopes of capturing the sound a bit more clearly? Maybe under the hood or something.

It almost sounds like a rattle outside the engine... There's an exhaust clamp after the downpipes that is metal on metal. It's so easy to get to you could check if it's loose real quick.

Otherwise it's really hard to tell through the video...

It seems to make the noise at ~3k RPM; if you hold it there with no load will it make the noise? If not it is unlikely to be the timing chain or an accessory, because they don't care if the car is accelerating or decelerating. They only care about the speed of the engine, and acceleration in terms of RPM/time, not the acceleration of the car.

good luck
Appreciate 0
      05-01-2017, 03:23 PM   #9
STR8-6IX
Banned
Canada
536
Rep
2,825
Posts

Drives: RWD 528i N52
Join Date: Nov 2016
Location: Toronto

iTrader: (0)

if the engine sounds fine under heavy load/ high RPM, and you cannot replicate the sound when the engine is not under load, I am starting to thing it is not the engine. possibly driveshaft, maybe transmission? something drivetrain related.

the Indy checked the motor and found it to be in good shape right? great choice on the oil/weight BTW. you know whats good when it comes to FBO.
Appreciate 1
      05-01-2017, 04:37 PM   #10
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

Quote:
Originally Posted by STR8-6IX View Post
if the engine sounds fine under heavy load/ high RPM, and you cannot replicate the sound when the engine is not under load, I am starting to thing it is not the engine. possibly driveshaft, maybe transmission? something drivetrain related.

the Indy checked the motor and found it to be in good shape right? great choice on the oil/weight BTW. you know whats good when it comes to FBO.
It's RPM related not speed related (watch the vids). RPM related means engine every time. It's just that it needs to be under heavy decel (i.e. extremely light load) that can't be recreated free-revving.
Appreciate 0
      05-01-2017, 08:21 PM   #11
austin
Private
24
Rep
80
Posts

Drives: '07 e90 335i
Join Date: Jul 2013
Location: CA

iTrader: (2)

Garage List
2007 e90 335i  [0.00]
I wouldn't be so quick to rule out a drivetrain issue. When in gear, engine RPM is tied to drivetrain RPM. So it could be that at a certain RPM something in the drivetrain is rattling, like the DMFW or the driveshaft carrier bearing. I've heard trans input shafts make some weird rattles too.

I'm not saying it necessarily is outside the engine, but I wouldn't rule it out entirely from a 10s video either.
Appreciate 0
      05-01-2017, 09:18 PM   #12
Holtdahooligan
New Member
United_States
6
Rep
13
Posts

Drives: 2013 BMW X5 35d
Join Date: Aug 2014
Location: Tampa, FL

iTrader: (0)

I really appreciate the suggestions and input guys. Only views and crickets from n54tech.

Belt and pulleys were replace ~500 miles ago so that's out. Water pump replaced ~1k ago.
I did have a slight chain "slapping" noise at idle back in january. A tech friend suggested a worn tensioner bolt, cleared that right up. Never got codes for this but replaced both Vanos solenoids just in case.

I do have oil consumption that increase with long highway trips (drinks 1qt every 3k miles). I have the RB upgraded pcv valve, replaced the plastic flapper hose and installed a catch can which has collected next to nothing over the years.

Running w/o primary and secondary cats, stock resonator and muffler delete. Friends have driven behind me and noted zero smoke from the exhaust during normal driving or WOT pulls. They have however seen small puffs of smoke under hard decel (*where I'm hearing my sound). Downpipe V- band clamps are not loose.

Don't believe it's drivetrain related. Transmissions been out, bolts, clutch, flywheel, mounts, driveshaft, differential have all be replaced. I know you can't tell from the videos but the sound is specifically coming from the from under the hood. I will attempt to borrow a GoPro and get a video from under the hood soon.

The noise only happens when in any gear, car moving at any speed and engine breaking from above 3k rpms. Not replicable while holding at a constant rpm, in neutral or with car in gear on a lift.
Appreciate 0
      05-01-2017, 09:36 PM   #13
NoQuarter
Captain
United_States
164
Rep
906
Posts

Drives: 2008 535xi / 2011 Z4 35Is
Join Date: Jan 2011
Location: Indiana

iTrader: (0)

Garage List
2018 BMW X2  [0.00]
2008 535xi  [0.00]
2011 Z4 35is  [0.00]
Does engine movement change appreciably when slowing down under load vs steady state/accelerating?

In other words... Instead of tilting left it tilts right further than it should be?
Appreciate 0
      05-02-2017, 01:46 AM   #14
Holtdahooligan
New Member
United_States
6
Rep
13
Posts

Drives: 2013 BMW X5 35d
Join Date: Aug 2014
Location: Tampa, FL

iTrader: (0)

Quote:
Originally Posted by NoQuarter View Post
Does engine movement change appreciably when slowing down under load vs steady state/accelerating?

In other words... Instead of tilting left it tilts right further than it should be?
Are you referring to the motor mounts being shot? I just last month installed the Ad engineering motor mounts. The car made the same noise before and after.
Appreciate 0
      05-02-2017, 02:31 AM   #15
Vincent_E90
Second Lieutenant
Vincent_E90's Avatar
United_States
81
Rep
241
Posts

Drives: N54 E90 335i 6MT BSM
Join Date: Sep 2014
Location: North Lake Tahoe, CA

iTrader: (1)

Keep me updated. Mine started to do this over the weekend a couple times. I tried to get it to do it again after work today but couldnt replicate it. Mine usually happens pre-boost and sometimes in decel like yours.

FBO, with catless downpipes. I am thinking it is the turbine catching but. Similar to you, no heavy smoke coming out.

How many miles on your turbos?
__________________
Mine - 2008 E90 335i Black Sapphire Metallic 6MT | New OEM Turbos @ 111k| Cobb Stage 2 LT Sport | Full Stainless Steel Akrapovic Exhaust | 5'' Stepped FMIC | VRSF Catless Downpipes| 19in BBS CH-R Matte Black | aFe Stage 2 Air Intake and air scoops| Mishimoto OCC| M-Tech Front Bumper
Appreciate 0
      05-02-2017, 08:40 AM   #16
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

A good option would be to go to a shop with a dyno and replicate the issue on the dyno with the hood popped so you can find the source. It'll cost dyno time, but it'll shorten the time to resolution.

ETA - I saw your thread on n54tech but only answered here because there's no reason for me to do double work
Appreciate 0
      05-02-2017, 09:08 AM   #17
NoQuarter
Captain
United_States
164
Rep
906
Posts

Drives: 2008 535xi / 2011 Z4 35Is
Join Date: Jan 2011
Location: Indiana

iTrader: (0)

Garage List
2018 BMW X2  [0.00]
2008 535xi  [0.00]
2011 Z4 35is  [0.00]
Broken bolts ? Maybe between engine and bellhousing?
Appreciate 0
      05-02-2017, 11:21 AM   #18
Vincent_E90
Second Lieutenant
Vincent_E90's Avatar
United_States
81
Rep
241
Posts

Drives: N54 E90 335i 6MT BSM
Join Date: Sep 2014
Location: North Lake Tahoe, CA

iTrader: (1)

Here's my sound, pretty similar

Sound starts around 7 seconds.



Over the weekend it was happening more on accelerating at 1/2 or 3/4 throttle passing 2500-3000rpm, I was not able to replicate it when recording yesterday after work. But caught it on video this morning coming in to work.
__________________
Mine - 2008 E90 335i Black Sapphire Metallic 6MT | New OEM Turbos @ 111k| Cobb Stage 2 LT Sport | Full Stainless Steel Akrapovic Exhaust | 5'' Stepped FMIC | VRSF Catless Downpipes| 19in BBS CH-R Matte Black | aFe Stage 2 Air Intake and air scoops| Mishimoto OCC| M-Tech Front Bumper
Appreciate 0
      05-02-2017, 04:15 PM   #19
Vincent_E90
Second Lieutenant
Vincent_E90's Avatar
United_States
81
Rep
241
Posts

Drives: N54 E90 335i 6MT BSM
Join Date: Sep 2014
Location: North Lake Tahoe, CA

iTrader: (1)

Was able to get a videos of the sound from idle.. This one you can hear throughout the video from under the car.



This one starts at ~37 seconds in.



are these similar to what you are hearing? Mine are at idle and can hear better from the side/under the car rather than the front.

I am thinking about checking my downpipes this weekend for a loose connection on the v bands. if they're all snug I am going to take them off and inspect them for any oil residue.

What actions have you done already?
__________________
Mine - 2008 E90 335i Black Sapphire Metallic 6MT | New OEM Turbos @ 111k| Cobb Stage 2 LT Sport | Full Stainless Steel Akrapovic Exhaust | 5'' Stepped FMIC | VRSF Catless Downpipes| 19in BBS CH-R Matte Black | aFe Stage 2 Air Intake and air scoops| Mishimoto OCC| M-Tech Front Bumper
Appreciate 0
      05-03-2017, 03:49 AM   #20
STR8-6IX
Banned
Canada
536
Rep
2,825
Posts

Drives: RWD 528i N52
Join Date: Nov 2016
Location: Toronto

iTrader: (0)

I have noticed it is quite common for the n54 to smoke on decel. I suggest this is what you look into regarding your problem.

sorry I could not be of more help
Appreciate 0
      05-03-2017, 07:26 AM   #21
dyezak
General of the Armies
dyezak's Avatar
United_States
156
Rep
655
Posts

Drives: X5M
Join Date: May 2011
Location: Plano, TX

iTrader: (1)

Quote:
Originally Posted by STR8-6IX View Post
I have noticed it is quite common for the n54 to smoke on decel. I suggest this is what you look into regarding your problem.

sorry I could not be of more help
That's generally the crappy pcv system.
Appreciate 0
      05-03-2017, 08:41 PM   #22
rismo
Captain
75
Rep
910
Posts

Drives: BMW E92 335
Join Date: Jul 2008
Location: Europe

iTrader: (0)

Probably your downpipes hitting some heat shield.
Weight distribution changes under decel.

At least I had this a couple of times when the DP's were a bit off...
Also can happen when re-aligning etc...

Hope this helps...
__________________
BMW 335 E92 09 - Full options - DKG - MHD by Buraq - RB Next Gen - RB Inlets/Outlet - Forge Diverter Valves - AR Catless DP - Afe Intake - Helix IC - FuelIT Stage 2 LPFP - Ar Oil Cooler - PPK Water Cooler - M3 Suspension - JRZ RS1 Shocks - Eibach Pro Springs - Drexler LSD - BMW IS Exhaust - Carbon Endurance Brake Pads - Stainless Steel Brake Lines - M101 Wheels - Michelin PS2 - M-Tech Body - M-Strutbar
BMW M550i G30 2019 - BM3
Appreciate 0
Reply

Bookmarks

Tags
chatter, deceleration, oil, starvation, whine

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:05 AM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST