E90Post
 


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

Posts: 89
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?
autoque is offline  
0
Reply With Quote
      08-23-2014, 11:23 AM   #2
TheAxiom
Dyno whore
 
Drives: E90 6Spd ZSP
Join Date: Nov 2013
Location: Tampa Florida

Posts: 1,801
iTrader: (1)

The sensor itself.
TheAxiom is offline   United_States
0
Reply With Quote
      08-25-2014, 06:41 AM   #3
autoque
Private
 
Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

Posts: 89
iTrader: (0)

I forgot to mention the eccentric shaft sensor was replaced, but no difference.
autoque is offline  
0
Reply With Quote
      08-25-2014, 06:45 AM   #4
TheSt|G
Resident Tamed Racing Driver
 
TheSt|G's Avatar
 
Drives: 911, 130is, E39 M5, E36 M3
Join Date: Mar 2008
Location: Outside Philly

Posts: 4,140
iTrader: (2)

When you unplug it and look in, do you see any oil?
TheSt|G is offline   United_States
0
Reply With Quote
      08-25-2014, 12:00 PM   #5
autoque
Private
 
Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

Posts: 89
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.
autoque is offline  
0
Reply With Quote
      08-25-2014, 02:03 PM   #6
TheSt|G
Resident Tamed Racing Driver
 
TheSt|G's Avatar
 
Drives: 911, 130is, E39 M5, E36 M3
Join Date: Mar 2008
Location: Outside Philly

Posts: 4,140
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.
__________________
130is MSport 6MT/ SuperSprint Headers & Exhaust with Swain Tech Race Coat / DISA Manifold / EVOLVE Tune / TCK DA Coilovers / Euro CF Intake/Box / BMW v1 Wheel / BBS RGRs with PSS / F30 Brake Shield / BMW CF Spoiler & Diffuser / Blackline Tails / Rear Fogs Enabled / Front Fogs Delete / CDV Delete / BMW Black Kidneys / M5 Illuminated Knob / BMW Stripe
TheSt|G is offline   United_States
0
Reply With Quote
      08-25-2014, 03:10 PM   #7
autoque
Private
 
Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

Posts: 89
iTrader: (0)

Absolutely no codes whatsoever. Checked at the dealer too.
autoque is offline  
0
Reply With Quote
      08-25-2014, 03:29 PM   #8
autoque
Private
 
Drives: '08 X5 3.0si
Join Date: Mar 2010
Location: Outside NA

Posts: 89
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.
autoque is offline  
0
Reply With Quote
      08-27-2014, 07:21 PM   #9
andy_bronze
Registered
 
Drives: 2009 328xi
Join Date: Aug 2013
Location: canada

Posts: 3
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.
andy_bronze is offline  
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 09:04 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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