Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E46 (1999 - 2006)

E46 (1999 - 2006)
The fourth generation 3 Series (E46 chassis) was introduced in 1999 and set the standard for engineering and performance during it's years of production including being named to Car & Driver's 10 best list every one of those years! ! -- View the E46 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 02-28-2008, 02:08 PM
vishmutzy vishmutzy is offline
Registered User
Location: Michigan
 
Join Date: Feb 2008
Posts: 8
Mein Auto: '01 325i Sport Wagon
E46 engine whistle - vacuum leak?

Hi folks,
I have a 2001 325i wagon, 5MT. Bought it about 3 weeks ago. The car has lived in Florida all it's life, recently brought to Michigan.

Just a few days ago I noticed a faint whistling noise coming from the engine compartment (I think). Today the noise was worse and the CEL came on. Here are all the symptoms I've noticed:

1) High pitched whistling noise between 2k-4k rpm, regardless of vehicle speed or gear.
2) Occasional rough idle (jumps between 500-1500 rpm).
3) Bellowing noise (about 3 second duration) when engine is shut down... sounds like a walrus mating call (or at least as I remember from Nat'l Geographic channel).
4) Check engine light (code?...I don't have an OBD reader).

I'm no expert, but it sure sounds like a vacuum leak. I've seen a few threads about somewhat similar issues, but I didn't want to get led in the wrong direction. Based on these symptoms, does anyone have any ideas?

My guess would be that the transition from warm, moist FL to VERY cold, dry MI may be causing all the vacuum hoses to contract. I just don't know which one(s) would be causing this issue.

Thank you much!
Braden
Reply With Quote
Advertisement
  #2  
Old 02-28-2008, 04:55 PM
Big "J" Big "J" is offline
Officially Welcomed to the 'Fest
Location: DFW
 
Join Date: Nov 2007
Posts: 483
Mein Auto: X5, 325I
Typically the plastic air intake hose will crack with age. From the air filter to the intake manifold check for a leak along that part.
Reply With Quote
  #3  
Old 02-29-2008, 09:15 PM
Daedalus34r's Avatar
Daedalus34r Daedalus34r is offline
Officially Welcomed to the 'Fest
Location: chicago
 
Join Date: Jun 2007
Posts: 398
Mein Auto: 04 330i
id like to add that im also having issues #2 and #3 from original post. rough idle occurs randomly, on trips, might occur constantly during a drive, or might not happen at all.

When the idle is rough, i do hear a hissing sound from behidn the dash.

No warnings lights have popped up.

any recommendations are most welcome, thanks!
Reply With Quote
  #4  
Old 03-02-2008, 09:37 PM
vishmutzy vishmutzy is offline
Registered User
Location: Michigan
 
Join Date: Feb 2008
Posts: 8
Mein Auto: '01 325i Sport Wagon
Here's an update on the suspected vacuum leak:
I pulled out the intake down to the throttle body, including the DISA (adjuster) valve and the ICV.
> Although the intake pipes weren't cracked, I replaced since I already had the parts.
> The small vacuum line that runs from the the intake pipe to the fuel canister was rotted at the ends, so I replaced with fresh tubing.
> I cleaned the ICV. The internals didn't seem to be seized, just a little dirty.
> The DISA adjuster valve was pretty gunked up and some of the gasket around the flapper seat was peeling off. I cleaned it up and leveled out the sealing surface the best I could.

After reassembling everything, I took it for a test drive tonight. The high-pitched vacuum noise appears to be gone, but there's still a sucking noise coming from within the intake manifold at the exact location of the DISA flapper. When I blip the throttle from idle, there's a very slight delay in throttle response and a "whoosh" sound coming from the same location. Also, the bellowing noise when I switch off the engine remains.

Logically, me thinks that the DISA flapper isn't sealing properly and the bellowing noise at shutdown is coming from its resonator. I'm considering ordering a new DISA unit. Since logic and I don't get along so well, does anyone have any advice?
Reply With Quote
  #5  
Old 03-03-2008, 02:46 PM
VSTOL VSTOL is offline
Registered User
Location: Arizona
 
Join Date: Jun 2007
Posts: 22
Mein Auto: 2000 323i
Vishmutzy Don't spring for a DISA valve, yet. The bellowing noise you hear upon engine shut-down may be due to a defective CCV; aka, cyclone valve, oil separator valve, or PCV valve.

You can search the forums and find quite a lot of info. Typically, when failed closed, they tend to honk or bellow for a few seconds when the engine is switched off. Briefly, this is due to extremely high vacuum in the top end of the motor.

Cheap, easy, but crude check: With the engine at idle, unlatch and slightly lift the oil cap on the valve cover. If there is a bunch of resistance to lifting the cap, vacuum is very high and often equals a defective oil separator. Also, the engine may produce the "bellowing" noise when you lift the cap.

Best way to check this is with a magnehelic gauge or a manometer, but that's another story. Good luck.
Reply With Quote
  #6  
Old 03-16-2008, 04:04 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Smile

Hi guys
I have exact same problem with my 318i, the engine model is the m43tu 1999 and all began some months ago now when I blew head gasget resulting from a coolant leak.

Shortly after the repair I noticed the same bellowing noise as described above and also had a CEL, turns out the cel is P0170 , fuel trim malfunction bank 1. Iv'e since stipt the intake manifold down numerous times in search of a vacuum leak. replacing all rubber gasgets for the second time, but still have same problem.

Also had main dealer take a look who diagnosed crankcase valve, replaced it and yep' still same problem.
I also replaced disa valve and cheekily returned it for a refund when i discovered the bloody noise was still there.

I'm sure the CEL is a direct result of this bellowing and just wish i could figure out whats causing it as it drives me crazy, any suggestions would be greatly appreciated.
Reply With Quote
  #7  
Old 03-17-2008, 11:59 AM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Anyone,,,?

Braden, how about you bruv did you figure out what the bellowing noise was, or do ya still have it?.
Reply With Quote
  #8  
Old 03-17-2008, 12:08 PM
^ECKS540i ^ECKS540i is offline
Registered User
Location: Lakewood, washington
 
Join Date: Mar 2008
Posts: 26
Mein Auto: 2000 540i6
Hey I know those symptoms!!! As a matter of fact I just had it replaced at the shop. Try looking into the "crank preassure relieve valve". Its on the backside of the intake manifold. Having that serviced/replaced will eliminate the CEL and the rough idling! I can get further more details for you guys tomarrow afternoon when i get my invoice for it!
Reply With Quote
  #9  
Old 03-17-2008, 02:36 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Quote:
Originally Posted by ^ECKS540i View Post
Hey I know those symptoms!!! As a matter of fact I just had it replaced at the shop. Try looking into the "crank preassure relieve valve". Its on the backside of the intake manifold. Having that serviced/replaced will eliminate the CEL and the rough idling! I can get further more details for you guys tomarrow afternoon when i get my invoice for it!
Hey ECKS540i thanks for the info,

I'm sure we are speaking of the same part and I changed it without making any difference to these damn symptoms, and each time I clear the fault code it just keeps coming back. After two drive cycles it just pops back up I can almost predict the moment that yellow glare is gonna come back to haunt me. Anyway I hope the fix works for you. keep us posted.
Reply With Quote
  #10  
Old 03-17-2008, 04:37 PM
vishmutzy vishmutzy is offline
Registered User
Location: Michigan
 
Join Date: Feb 2008
Posts: 8
Mein Auto: '01 325i Sport Wagon
I took VSTOL's advice and replaced the oil separator and all 4 hoses (3 attached to separator + crossover hose on top of intake manifold). There was plenty of oil/condensation "mayo" in the valve, but no black gunky stuff.

the intake hisses, whistles and whooses seem to be reduced. I still get the bellow during shutdown, but it's not as loud. I haven't driven the car enough since I replaced the oil separator to make a final judgment, but I'd say it was a success. And no CEL's yet. Thanks for the advice VSTOL!

ECKS540i: I'd be interested to know the details of that "crank pressure relieve valve". I've never heard of such a device, but I'm willing to look into it. Let me know if you can get a part number.

Thanks everyone!
Reply With Quote
  #11  
Old 06-05-2008, 05:24 AM
bjt bjt is offline
Registered User
Location: London
 
Join Date: Jun 2008
Posts: 3
Mein Auto: E36 Compact
Quote:
Originally Posted by marmite View Post
I'm sure we are speaking of the same part and I changed it without making any difference to these damn symptoms, and each time I clear the fault code it just keeps coming back.
I have the exact same problem as well (whooshing sound at shutdown, P0170 code) in my E36 compact (which has the M43 engine as well). Did you have any luck finding a solution? Tried cleaning the MAF so far, I am off to the dealer to get a crank case valve and the hose today.

The code refers to Long Term Fuel Trim, on my car it's up around +20%. Seems to indicate the trim is compensating for a lean condition. So far I think it could be caused by any of the following:

- Bad pre-cat O2
- Bad PCV
- Vac leak
- Exhaust leak before the precat O2
- Bad MAF
Reply With Quote
  #12  
Old 06-05-2008, 06:10 AM
sixkiller sixkiller is offline
Registered User
Location: Fort Worth, Texas
 
Join Date: Mar 2008
Posts: 86
Mein Auto: 2002 325 ci
That's what it sounds like to me...just got mine in the mail. oil seperator / crankcase vent valve. The part is $44 from oembimmerparts.com, $42 from pelicanparts and $52 from bimmerworld.

hope it fixes your problem....you should see a slight increase in gas mileage all things considered.
__________________
SIXKILLER

Last edited by sixkiller; 06-05-2008 at 06:15 AM.
Reply With Quote
  #13  
Old 06-05-2008, 10:16 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Thumbs up

Hi bjt

I finally found the solution to the the problem about 2 weeks ago now. After finding a post on how to get my more advanced obd2 code reader to work, I found that LTFT was stuck at 23% . So with this new info I did some searches on live engine data and all symptoms were pointing towards a bad MAF, and sure enough thats what it was.

Check out faulty maf diagnosis at motor.com. Apparently when a maf has had its day it over estimates air flow at cruising speed and under est at idle, and I could see this hapening whaching the live data. At idle the LTFT would gradually come down to about 18% and contiue to fall, but as soon as I opened the throttle it would creep back up again.

My car now accelerates alot quicker under load, with a considerable increase in torque.
I solved the bellowing noise that occured on shut down with a new battery, I cant be sure but i think that the disa valve was getting lazy due too the drop in voltage.

Its surprising how a gradually deteriorating part can cause drivability changes to go unnoticed.

Anyway good luck, hope you find a solution soon:
Reply With Quote
  #14  
Old 06-06-2008, 11:22 AM
bjt bjt is offline
Registered User
Location: London
 
Join Date: Jun 2008
Posts: 3
Mein Auto: E36 Compact
Smile

Great, glad you got it sorted out. I'll start looking for a new MAF for mine as well, maybe I can get one cheap off eBay...

Replacing the crankcase valve did nothing for me either.

Looked at the article you mentioned, it's very helpful. Out of interest, do you remember what your load and air flow figures were at idle? I was getting around 20% load and 2.4g/s air flow at idle.

I've attached the scans information I got at idle, please let me know if anything looks similar to what you saw... thanks!
Attached Thumbnails
Click image for larger version

Name:	freeze2.JPG
Views:	1212
Size:	38.8 KB
ID:	149309   Click image for larger version

Name:	3.JPG
Views:	882
Size:	44.1 KB
ID:	149310   Click image for larger version

Name:	4.JPG
Views:	765
Size:	50.2 KB
ID:	149311   Click image for larger version

Name:	1.JPG
Views:	811
Size:	64.0 KB
ID:	149312  

Last edited by bjt; 06-06-2008 at 11:26 AM.
Reply With Quote
  #15  
Old 06-06-2008, 09:22 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Hi bjt

Just had a look at the first set of freeze frame you posted, and going over what I had recorded, our readings look almost identical.
I posted above that LTFT was 23% but looking again it was the same as yours 20.3% which must be the upper fueltrim limit set by bmw for this engine. Load 18% and airflow also very very similar.

I'd say without doubt that a new MAF will cure your problem, but having said that I have also read that some aftermarket MAF's from ebay have caused more problems, so beware of that.
I got my one from eurocar parts here in uk for 75 and it works just fine.

anyway goodluck
Reply With Quote
  #16  
Old 06-07-2008, 04:39 AM
simon325e's Avatar
simon325e simon325e is offline
Mod the driver
Location: NJ
 
Join Date: Jul 2007
Posts: 340
Mein Auto: BMW
Same issue

I currently have the same noise. Since my car had a new MAF about a year and a half ago is it possible there is some other root cause? Just wondering if any has had any experience with multiple MAFs going bad.
Reply With Quote
  #17  
Old 06-07-2008, 11:42 AM
Keyser Soze's Avatar
Keyser Soze Keyser Soze is offline
just like that, he's gone
Location: Northern California
 
Join Date: Oct 2003
Posts: 1,488
Mein Auto: 2013 535
check the intake boot between the manifold and MAF, it's rubber and breaks down and splits after 5 years or so

Quote:
Originally Posted by simon325e View Post
I currently have the same noise. Since my car had a new MAF about a year and a half ago is it possible there is some other root cause? Just wondering if any has had any experience with multiple MAFs going bad.
__________________
2013 F10 535i M-Sport, Sophisto Grau, 6-speed MT
2011 E90 335i Sport, Jet Black, Sport Auto, Performance Edition
2002 E46 330i Sport, Jet Black, 5-speed MT, lots of upgrades
2001 E46 330Ci Sport, Steel Grey, 5-speed MT....and more

Reply With Quote
  #18  
Old 06-08-2008, 09:04 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
HI simone 325e
as my previous post says , the new MAF cured the fuel trim malfunction P0170 cel and a new BATTERY fixed the bellowing noise on shut down so I would say the lack of charge in the battery would be the root cause you seek. A MAF going bad would not cause strange intake noises.
so if your battery is more than say three years old it may be time for a new one .
good luck and keep us posted.
Reply With Quote
  #19  
Old 06-12-2008, 05:27 AM
bjt bjt is offline
Registered User
Location: London
 
Join Date: Jun 2008
Posts: 3
Mein Auto: E36 Compact
Thumbs up Fixed

Thanks for the information marmite, it was absolutely spot on. Went down to ECP and got a new MAF, changed it over and fired her up. Immediately I noticed that the short term fuel trim was around -20.3%, while the long term was still 20.3%. Went for a drive up the motorway and back (around 30 miles) and when I got back the long term fuel trim was at 0%, short term around 0% as well.

The car accelerates much better, in fact I had to pay attention to keep it at 30, guess I'm not used to it. The engine sound much smoother under load as well, I can floor it without getting the knocking noise I heard before (was running lean I guess).

I had tried cleaning the old MAF, no luck though. It had 100k on it so I guess it was well past it.
Reply With Quote
  #20  
Old 06-12-2008, 01:38 PM
marmite marmite is offline
Registered User
Location: London
 
Join Date: Mar 2008
Posts: 12
Mein Auto: bmw 318i e46
Hi bjt
Excelent news,. the amount of time i spent looking for a fix to this problem. Im glad I could help,
Reply With Quote
  #21  
Old 06-16-2008, 06:41 AM
sixkiller sixkiller is offline
Registered User
Location: Fort Worth, Texas
 
Join Date: Mar 2008
Posts: 86
Mein Auto: 2002 325 ci
Can someone give me the location of where the oil seperator valve is in the engine compartment? I have pulled up the schematic on realoemparts and it shows to be on the driver side but where? Under the manifold? Under the airbox? I do not want to start removing a bunch of parts until I know it's location.

thank you
__________________
SIXKILLER
Reply With Quote
  #22  
Old 06-16-2008, 08:54 AM
Lbert Lbert is offline
Officially Welcomed to the 'Fest
Location: Richardson, TX
 
Join Date: Oct 2006
Posts: 409
Mein Auto: 325i
Yes, the oil separator is underneath the manifold. It is very well hidden. You will need to remove numerous parts to view it. However you can see looking up from underneath the car.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E46 (1999 - 2006)
Today's Posts Search
Thread Tools
Display Modes

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 On



Forum Jump


All times are GMT -7. The time now is 04:28 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms