E90Post
 


GetBMWParts
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > NA Engine (non-turbo) / Drivetrain / Exhaust Modifications > o2 Sensor Wiring



Reply
 
Thread Tools Search this Thread
      03-24-2013, 05:20 AM   #1
MikeR1994
Second Lieutenant
 
Drives: 06 e90 325i, 05 325Ci (RIP)
Join Date: Sep 2011
Location: Charlotte, NC

Posts: 223
iTrader: (0)

Garage List
2006 BMW 325i  [0.00]
o2 Sensor Wiring

Alrighty. My last thread didn't get much attention so I'm gonna dumb it down a bit. Does anyone know what harness the wiring for the o2 sensors is on? I know on the s54 it is actually on the engine trans module wiring harness, but I figure it could be on the engine wiring harness on other cars. I've looked at parts diagrams but I really can't pick out the o2 connectors in any of them since they show so little detail.
__________________
-Michael
Active Autowerke Stage II | MMW CSv2 Exhaust | MMW Catless Headers | BC Racing BR Extreme Low Coilovers | custom adjustable rear suspension links | 19" Hyperblack CSL's | M3 style front | trim wrapped in brushed steel vinyl | Slightly smoked tail lights with clear reverse lights | factory xenons

MikeR1994 is offline   United_States
0
Reply With Quote
      03-24-2013, 06:55 AM   #2
Efthreeoh
Colonel
 
Drives: E90
Join Date: May 2012
Location: MARLAND

Posts: 2,445
iTrader: (0)

I'll take a shot at this. I looked at the harness drawings on realoem and having replaced one of the pre-cat sensors I know where the sensor harness connects to the main harness. I'd say the two pre-cat O2 sensors connect to the main engine harness because they wrap around the rear of the valve cover and then connect into the harness on the intake-side of the engine.

The post-cat O2 sensors, I'd bet connect to the transmission harness since they are closer to the trans at the bottom of the car.

This is pure deduction on my part as by looking at the three wiring harness pictures in the Engine Electrical section of realoem for a 2006 325i (N52). The "Engine wiring harness, engine module" harness has two identical looking connectors, which is how it is set up on the engine where the two pre-cat sensors connect to (one connector is white, the other is gray). The "wiring harness, engine trans. module" harness also has two identical looking connectors on it as well, which indicates two of the same-type connectors are used on it that I would suspect to be the connectors for the two post-cat O2 sensors.

Hope this helps.
Efthreeoh is offline   United_States
0
Reply With Quote
      03-25-2013, 08:35 AM   #3
MikeR1994
Second Lieutenant
 
Drives: 06 e90 325i, 05 325Ci (RIP)
Join Date: Sep 2011
Location: Charlotte, NC

Posts: 223
iTrader: (0)

Garage List
2006 BMW 325i  [0.00]
Quote:
Originally Posted by Efthreeoh View Post
I'll take a shot at this. I looked at the harness drawings on realoem and having replaced one of the pre-cat sensors I know where the sensor harness connects to the main harness. I'd say the two pre-cat O2 sensors connect to the main engine harness because they wrap around the rear of the valve cover and then connect into the harness on the intake-side of the engine.

The post-cat O2 sensors, I'd bet connect to the transmission harness since they are closer to the trans at the bottom of the car.

This is pure deduction on my part as by looking at the three wiring harness pictures in the Engine Electrical section of realoem for a 2006 325i (N52). The "Engine wiring harness, engine module" harness has two identical looking connectors, which is how it is set up on the engine where the two pre-cat sensors connect to (one connector is white, the other is gray). The "wiring harness, engine trans. module" harness also has two identical looking connectors on it as well, which indicates two of the same-type connectors are used on it that I would suspect to be the connectors for the two post-cat O2 sensors.

Hope this helps.
I decided the best way to figure it out was just to trace the wires back to the source. That wasn't too much of a challenge to do, but I found out it goes into the waterproof box for the DME in the meddle of the three rubber grommet kind of things. I'm going to double check today, but I'm pretty sure the ignition wires all lead in there too! I think I'm getting somewhere.
__________________
-Michael
Active Autowerke Stage II | MMW CSv2 Exhaust | MMW Catless Headers | BC Racing BR Extreme Low Coilovers | custom adjustable rear suspension links | 19" Hyperblack CSL's | M3 style front | trim wrapped in brushed steel vinyl | Slightly smoked tail lights with clear reverse lights | factory xenons

MikeR1994 is offline   United_States
0
Reply With Quote
      03-27-2013, 09:44 AM   #4
MikeR1994
Second Lieutenant
 
Drives: 06 e90 325i, 05 325Ci (RIP)
Join Date: Sep 2011
Location: Charlotte, NC

Posts: 223
iTrader: (0)

Garage List
2006 BMW 325i  [0.00]
I was mistaken about the whole ignition thing. I traced the wires back to the main engine wiring harness. I'm just gonna replace the o2 sensor itself today and hope that it was the problem. I guess it would make sense as I'm at 80k, tuned since 60k or so, and for the last 1,000 or so my air/fuel ratio has been extremely rich, so maybe it was just a coincidence.
__________________
-Michael
Active Autowerke Stage II | MMW CSv2 Exhaust | MMW Catless Headers | BC Racing BR Extreme Low Coilovers | custom adjustable rear suspension links | 19" Hyperblack CSL's | M3 style front | trim wrapped in brushed steel vinyl | Slightly smoked tail lights with clear reverse lights | factory xenons

MikeR1994 is offline   United_States
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 02:52 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