E90Post
 


TireRack
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Do I need secondary 02 Sensors?



Reply
 
Thread Tools Search this Thread
      01-01-2014, 09:55 PM   #1
Tim603
Major
United_States
20
Rep
1,081
Posts

 
Drives: 2007 335i E90
Join Date: Feb 2012
Location: North Canton, OH

iTrader: (3)

Do I need secondary 02 Sensors?

If I have the tune to eliminate the emissions codes thrown by catless headers Do I still need secondary 02 sensors?

Arent the secondary 02 sensors just there for emissions purposes?

Supposes I had one secondary 02 sensor plugged in just not screwed into the exhaust (just set off to the side), would this work or does it need to be in the flow of the exhaust?

Thanks for any input guys

BTW this is for N52 I just wanted to see if any of you N54 guys had any input on this matter
__________________
Just picked up an E90 07 335

Bone stock.....for now
Appreciate 0
      01-01-2014, 09:58 PM   #2
pwr hungry
Banned
14
Rep
1,260
Posts

 
Drives: 335
Join Date: Mar 2013
Location: Amer'ca

iTrader: (2)

You must have the secondary O2 sensor for the car to run correctly.
Appreciate 0
      01-02-2014, 09:34 AM   #3
Ingeniator
Major
Ingeniator's Avatar
Canada
12
Rep
1,085
Posts

 
Drives: 07 335XI(90) 09 135I(82)
Join Date: Nov 2013
Location: Fort Mac, Alberta

iTrader: (1)

Quote:
Originally Posted by pwr hungry View Post
You must have the secondary O2 sensor for the car to run correctly.
Why?

Unless BMW has invented magic cats secondary O2 sensors are not needed. If you leave them plugged in they will probably still throw codes because they won't warm up. But you said you had a tuner that can ignore/auto clear those. Narrow band O2's are used pre cats to measure stoic/lambda the ECM then compares that signal with the reading from post cat sensors and it determines the Cat efficiency and flags if it does not meet emissions compliance.
__________________
07 335XI (A008006) 6AT ~94K miles JB4 G5 ISO VSRF DP's
09 135I M (VK80379) 6MT. Race Project car. 1) Install Cobb/piggyback? and Motiv 600 Kit[HTA3076R w/ tial .82] 2) JRZ or Moton suspension. 3) Build high flow intake manifold with multi-port fuel and relocate OFH 4) Build full cage 5) Complete staged twin setup with HTA4205R [w/Tial 1.16] 6) Complete dry sump system
Appreciate 0
      01-02-2014, 11:33 AM   #4
Tim603
Major
United_States
20
Rep
1,081
Posts

 
Drives: 2007 335i E90
Join Date: Feb 2012
Location: North Canton, OH

iTrader: (3)

Quote:
Originally Posted by Ingeniator View Post
Why?

Unless BMW has invented magic cats secondary O2 sensors are not needed. If you leave them plugged in they will probably still throw codes because they won't warm up. But you said you had a tuner that can ignore/auto clear those. Narrow band O2's are used pre cats to measure stoic/lambda the ECM then compares that signal with the reading from post cat sensors and it determines the Cat efficiency and flags if it does not meet emissions compliance.
The tune clears the emissions code, I will try and unplug it completely and see if it throws any
__________________
Just picked up an E90 07 335

Bone stock.....for now
Appreciate 0
      01-02-2014, 11:34 AM   #5
dallas_jeff
Second Lieutenant
United_States
2
Rep
267
Posts

 
Drives: 2008 E90
Join Date: Feb 2013
Location: Dallas, TX

iTrader: (3)

Do the secondary 02 sensors not affect the AFR's?
__________________
Bronze Metallic E90 335i, JB4 w/ backend flash, Cobb FMIC, BMS Downpipes, BMS DCI, Remus Race Exhaust, RB Turbos, E85/93, Wavetrac LSD, Diff lockdown, M3 control arms, M3 rear guide rod, M3 subframe bushings.
Appreciate 0
      01-02-2014, 11:38 AM   #6
MDORPHN
Colonel
41
Rep
2,550
Posts

 
Drives: AW 1M
Join Date: Oct 2010
Location: Wash, DC

iTrader: (0)

Quote:
Originally Posted by dallas_jeff View Post
Do the secondary 02 sensors not affect the AFR's?
As I understand it, they primarily monitor the efficiency of the cats but may have a very slight effect on long term fuel trim.

Neil
Appreciate 0
      01-03-2014, 12:30 AM   #7
Shadow007
First Lieutenant
United_States
6
Rep
388
Posts

 
Drives: 2009 335i coupe monaco blue
Join Date: Apr 2012
Location: El Paso, TX

iTrader: (2)

I'm going to need new 02 sensors. I have the worst gas mileage in history. Consecutive 12.4 mpg
Appreciate 0
      01-03-2014, 01:32 PM   #8
dallas_jeff
Second Lieutenant
United_States
2
Rep
267
Posts

 
Drives: 2008 E90
Join Date: Feb 2013
Location: Dallas, TX

iTrader: (3)

Quote:
Originally Posted by Shadow007 View Post
I'm going to need new 02 sensors. I have the worst gas mileage in history. Consecutive 12.4 mpg
Wow! Are you using e85? On 60% E85, I'm still getting right around 15 mpg with mostly city driving.
__________________
Bronze Metallic E90 335i, JB4 w/ backend flash, Cobb FMIC, BMS Downpipes, BMS DCI, Remus Race Exhaust, RB Turbos, E85/93, Wavetrac LSD, Diff lockdown, M3 control arms, M3 rear guide rod, M3 subframe bushings.
Appreciate 0
      01-03-2014, 01:37 PM   #9
135Pats
Turbo's Here
135Pats's Avatar
United_States
62
Rep
5,703
Posts

 
Drives: 135i
Join Date: May 2012
Location: Maryland

iTrader: (2)

That doesn’t sound too nutty if you have some E85 in the tank. If you spend the majority of your time starting and stopping one block to another (every single day in DC), you won’t average much more than 15/gal max. 14 gallon tank in my 1er gets me about 200 miles; daily commute is slogging through the District.
__________________
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Meisterschaft Race/Berk Resonated/ER CP/Synapse/VRSF FMIC/FFTEC LPFP/HFS-4 DO Stainless Lines/BMS Thermostat Delete/Rob Beck PCV Valve + Cap/BMS OCC/ST Coilovers/M3 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance
Appreciate 0
      01-03-2014, 04:39 PM   #10
Shadow007
First Lieutenant
United_States
6
Rep
388
Posts

 
Drives: 2009 335i coupe monaco blue
Join Date: Apr 2012
Location: El Paso, TX

iTrader: (2)

Quote:
Originally Posted by dallas_jeff View Post
Wow! Are you using e85? On 60% E85, I'm still getting right around 15 mpg with mostly city driving.
Nah man I only use 93 octane. I guess I should pay attention to the codes that pop up on the jb4. Every time the check engine light pops on, I read the code which is two o2 related problems and then I erase them. Now I see the results of my foolish ways
Appreciate 0
      01-03-2014, 07:07 PM   #11
dallas_jeff
Second Lieutenant
United_States
2
Rep
267
Posts

 
Drives: 2008 E90
Join Date: Feb 2013
Location: Dallas, TX

iTrader: (3)

Quote:
Originally Posted by Shadow007 View Post
Nah man I only use 93 octane. I guess I should pay attention to the codes that pop up on the jb4. Every time the check engine light pops on, I read the code which is two o2 related problems and then I erase them. Now I see the results of my foolish ways
Oh yeah don't ignore 02 sensor codes. I had those codes, so I replaced all 4 02 sensors, and they haven't come back.
__________________
Bronze Metallic E90 335i, JB4 w/ backend flash, Cobb FMIC, BMS Downpipes, BMS DCI, Remus Race Exhaust, RB Turbos, E85/93, Wavetrac LSD, Diff lockdown, M3 control arms, M3 rear guide rod, M3 subframe bushings.
Appreciate 0
      01-03-2014, 07:25 PM   #12
135Pats
Turbo's Here
135Pats's Avatar
United_States
62
Rep
5,703
Posts

 
Drives: 135i
Join Date: May 2012
Location: Maryland

iTrader: (2)

Replace the relevant o2s if you are getting codes, they take a lot of heat and fail/crack with frequency. I've replaced both rears on my 1er, both fronts on my E90.

Especially if it's the narrowband o2, you really don't want to be driving a lot with that. You'll have some silly AFRs.
__________________
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Meisterschaft Race/Berk Resonated/ER CP/Synapse/VRSF FMIC/FFTEC LPFP/HFS-4 DO Stainless Lines/BMS Thermostat Delete/Rob Beck PCV Valve + Cap/BMS OCC/ST Coilovers/M3 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance
Appreciate 0
      01-03-2014, 08:45 PM   #13
dlbrooks18
Brigadier General
dlbrooks18's Avatar
52
Rep
3,583
Posts

 
Drives: e90 335i
Join Date: Nov 2008
Location: Los Angeles

iTrader: (2)

Quote:
Originally Posted by Ingeniator View Post
Why?

Unless BMW has invented magic cats secondary O2 sensors are not needed. If you leave them plugged in they will probably still throw codes because they won't warm up. But you said you had a tuner that can ignore/auto clear those. Narrow band O2's are used pre cats to measure stoic/lambda the ECM then compares that signal with the reading from post cat sensors and it determines the Cat efficiency and flags if it does not meet emissions compliance.
Is performance affected/timing pulled etc., or just codes thrown?
__________________

2008 E90 335
Appreciate 0
      01-04-2014, 02:02 PM   #14
BMWM.D.
Stupid Idiot
BMWM.D.'s Avatar
8
Rep
687
Posts

 
Drives: E90 335i & C6 Grand Sport
Join Date: May 2009
Location: Santa Barbara

iTrader: (1)

Quote:
Originally Posted by Ingeniator View Post
Narrow band O2's are used pre cats to measure stoic/lambda the ECM then compares that signal with the reading from post cat sensors and it determines the Cat efficiency and flags if it does not meet emissions compliance.
Maybe this was just a typo..... but the N54 uses wideband pre-cat (control) oxygen sensors. The post-cat sensors are regular narrow band 02 sensors.
__________________
Appreciate 0
      01-04-2014, 10:32 PM   #15
Ingeniator
Major
Ingeniator's Avatar
Canada
12
Rep
1,085
Posts

 
Drives: 07 335XI(90) 09 135I(82)
Join Date: Nov 2013
Location: Fort Mac, Alberta

iTrader: (1)

Quote:
Originally Posted by BMWM.D. View Post
Maybe this was just a typo..... but the N54 uses wideband pre-cat (control) oxygen sensors. The post-cat sensors are regular narrow band 02 sensors.
Interesting. I don't profess to be an N54 expert. I mostly have JDM and V8 experience. If we use wideband in the front are they Bosch or NGK sensors. I'm surprised not many OEM's use wideband because they are not needed for everyday engines as they can adjust the known maps easily in the cheaper narrowband range and wideband typically are not as robust leading to premature failure.
__________________
07 335XI (A008006) 6AT ~94K miles JB4 G5 ISO VSRF DP's
09 135I M (VK80379) 6MT. Race Project car. 1) Install Cobb/piggyback? and Motiv 600 Kit[HTA3076R w/ tial .82] 2) JRZ or Moton suspension. 3) Build high flow intake manifold with multi-port fuel and relocate OFH 4) Build full cage 5) Complete staged twin setup with HTA4205R [w/Tial 1.16] 6) Complete dry sump system
Appreciate 0
      01-04-2014, 11:07 PM   #16
Tim603
Major
United_States
20
Rep
1,081
Posts

 
Drives: 2007 335i E90
Join Date: Feb 2012
Location: North Canton, OH

iTrader: (3)

Quote:
Originally Posted by dlbrooks18 View Post
Is performance affected/timing pulled etc., or just codes thrown?
I didnt think that any performance was affected but I ended up welding a new bung onto my catless headers and once the o2 sensor was inserted all the codes have gone away (thus far, crossing fingers) and it seems to be responding better. Long story short, you need secondary o2 sensors in the exhaust stream. I tried every way around it and all my car did was throw codes
__________________
Just picked up an E90 07 335

Bone stock.....for now
Appreciate 0
      01-04-2014, 11:25 PM   #17
dlbrooks18
Brigadier General
dlbrooks18's Avatar
52
Rep
3,583
Posts

 
Drives: e90 335i
Join Date: Nov 2008
Location: Los Angeles

iTrader: (2)

Quote:
Originally Posted by Tim603 View Post
I didnt think that any performance was affected but I ended up welding a new bung onto my catless headers and once the o2 sensor was inserted all the codes have gone away (thus far, crossing fingers) and it seems to be responding better. Long story short, you need secondary o2 sensors in the exhaust stream. I tried every way around it and all my car did was throw codes
Thanks, any pics of the bung?
__________________

2008 E90 335
Appreciate 0
      01-04-2014, 11:32 PM   #18
Tim603
Major
United_States
20
Rep
1,081
Posts

 
Drives: 2007 335i E90
Join Date: Feb 2012
Location: North Canton, OH

iTrader: (3)

Quote:
Originally Posted by dlbrooks18 View Post
Thanks, any pics of the bung?
you know i almost took some pics at the exhaust shop but this time of year there is snow, slush and water dripping everywhere so I didnt bother. If I take some tho Ill post them!
__________________
Just picked up an E90 07 335

Bone stock.....for now
Appreciate 0
      01-04-2014, 11:33 PM   #19
Ingeniator
Major
Ingeniator's Avatar
Canada
12
Rep
1,085
Posts

 
Drives: 07 335XI(90) 09 135I(82)
Join Date: Nov 2013
Location: Fort Mac, Alberta

iTrader: (1)

Quote:
Originally Posted by Tim603 View Post
I didnt think that any performance was affected but I ended up welding a new bung onto my catless headers and once the o2 sensor was inserted all the codes have gone away (thus far, crossing fingers) and it seems to be responding better. Long story short, you need secondary o2 sensors in the exhaust stream. I tried every way around it and all my car did was throw codes
Looks like the cross reference shows they are bosch wideband. That is a pretty sweet finding. This also means they probably use the rear sensor to help calibrate the front wideband. Which would explain why issues occur when not running them overtime.
__________________
07 335XI (A008006) 6AT ~94K miles JB4 G5 ISO VSRF DP's
09 135I M (VK80379) 6MT. Race Project car. 1) Install Cobb/piggyback? and Motiv 600 Kit[HTA3076R w/ tial .82] 2) JRZ or Moton suspension. 3) Build high flow intake manifold with multi-port fuel and relocate OFH 4) Build full cage 5) Complete staged twin setup with HTA4205R [w/Tial 1.16] 6) Complete dry sump system
Appreciate 0
      01-04-2014, 11:36 PM   #20
dlbrooks18
Brigadier General
dlbrooks18's Avatar
52
Rep
3,583
Posts

 
Drives: e90 335i
Join Date: Nov 2008
Location: Los Angeles

iTrader: (2)

Quote:
Originally Posted by Tim603 View Post
you know i almost took some pics at the exhaust shop but this time of year there is snow, slush and water dripping everywhere so I didnt bother. If I take some tho Ill post them!
Cool, thanks!
__________________

2008 E90 335
Appreciate 0
      01-05-2014, 12:29 AM   #21
ashmostro
Lieutenant Colonel
ashmostro's Avatar
United_States
20
Rep
1,760
Posts

 
Drives: '13 335is DCT
Join Date: Jan 2013
Location: Vienna, VA

iTrader: (9)

The secondary sensors help keep the primaries calibrated... you need them even with dps.
Appreciate 0
      01-05-2014, 02:10 AM   #22
Allen@MOTIV
BimmerPost Supporting Vendor
7
Rep
605
Posts


 
Drives: 135i
Join Date: Jun 2013
Location: VA

iTrader: (0)

Quote:
Originally Posted by Ingeniator View Post
Looks like the cross reference shows they are bosch wideband. That is a pretty sweet finding. This also means they probably use the rear sensor to help calibrate the front wideband. Which would explain why issues occur when not running them overtime.
Bingo
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
Forum Jump


All times are GMT -5. The time now is 10:30 PM.




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