E90Post
 


 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > NA Engine (non-turbo) / Drivetrain / Exhaust Modifications > Rough warm start, but fine without eccentric shaft sensor



Reply
 
Thread Tools Search this Thread
      08-23-2014, 10:55 AM   #1
autoque
Private
8
Rep
89
Posts

Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

iTrader: (0)

Exclamation Rough warm start, but fine without eccentric shaft sensor

I've got a '08 N52 3.0 naturally aspirated motor. At every warm start, the engine runs rough for like 1 to 2 minutes. It almost disappears after about 2 minutes but a sensitive person can still feel some unevenness in idle whenever I'm stopped.
But when I unplug the eccentric shaft sensor, the symptom doesn't show up anymore. From what I've researched, unplugging the eccentric shaft sensor disables valvetronic and the valve lift is set to maximum at idle.
I've also heard, for N52 engines, the valve lift can't be adjusted as it's automatic.
So which parts of valvetronic should I replace to fix this issue?
Appreciate 0
      08-23-2014, 11:23 AM   #2
Taskmaster
Banned
Japan
2463
Rep
9,004
Posts

Drives: M235i 6MT / E92 328 Msport 6MT
Join Date: Nov 2013
Location: Florida

iTrader: (6)

The sensor itself.
Appreciate 0
      08-25-2014, 06:41 AM   #3
autoque
Private
8
Rep
89
Posts

Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

iTrader: (0)

I forgot to mention the eccentric shaft sensor was replaced, but no difference.
Appreciate 0
      08-25-2014, 06:45 AM   #4
TheSt|G
Resident Tamed Racing Driver
TheSt|G's Avatar
United_States
292
Rep
4,697
Posts

Drives: 911, 130is, E39 M5, E36 M3
Join Date: Mar 2008
Location: Outside Philly

iTrader: (2)

When you unplug it and look in, do you see any oil?
Appreciate 0
      08-25-2014, 12:00 PM   #5
autoque
Private
8
Rep
89
Posts

Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

iTrader: (0)

Quote:
Originally Posted by TheSt|G View Post
When you unplug it and look in, do you see any oil?
Yes, the eccentric shaft sensor had oil in it. Cleaned and plugged back in, same symptom. So replaced it but still no difference. It must be something else. BTW, coil and spark plugs have been replaced before, as well as maf but no change. Something in the valvetronic I think... I tried unplugging the vanos solenoid to disable vanos, but the symptom remained, so it may not be vanos, but suspicion is on the valvetronic.
Appreciate 0
      08-25-2014, 02:03 PM   #6
TheSt|G
Resident Tamed Racing Driver
TheSt|G's Avatar
United_States
292
Rep
4,697
Posts

Drives: 911, 130is, E39 M5, E36 M3
Join Date: Mar 2008
Location: Outside Philly

iTrader: (2)

Quote:
Originally Posted by autoque View Post
Yes, the eccentric shaft sensor had oil in it. Cleaned and plugged back in, same symptom. So replaced it but still no difference. It must be something else. BTW, coil and spark plugs have been replaced before, as well as maf but no change. Something in the valvetronic I think... I tried unplugging the vanos solenoid to disable vanos, but the symptom remained, so it may not be vanos, but suspicion is on the valvetronic.
Have you pulled the codes? That would be the first place to start. The valvetronic is not particularly known for failure.
__________________
2005 E46 M3 Interlagos/Cinnamon with Sunroof Delete
Appreciate 0
      08-25-2014, 03:10 PM   #7
autoque
Private
8
Rep
89
Posts

Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

iTrader: (0)

Absolutely no codes whatsoever. Checked at the dealer too.
Appreciate 0
      08-25-2014, 03:29 PM   #8
autoque
Private
8
Rep
89
Posts

Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

iTrader: (0)

Quote:
Originally Posted by TheSt|G View Post
The valvetronic is not particularly known for failure.
I'd think so too, but I can't pinpoint the problem at the moment to any particular part. Took off the valve cover and camshafts/eccentric shaft look fine with no particular wear pattern.
Appreciate 0
      08-27-2014, 07:21 PM   #9
andy_bronze
New Member
0
Rep
9
Posts

Drives: 2009 328xi
Join Date: Aug 2013
Location: canada

iTrader: (0)

I have the same problem and been trying to solve it for months. No luck so far. The other thing I also noticed is if I do not drive the car for a day or longer then even a cold start takes a little longer, otherwise cold starts are fine.
Appreciate 0
Reply

Bookmarks

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 09:28 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