Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: V8Cowboy on 06 August 2013, 11:41:28

Title: Pre cat / post cat o2 sensor technically the same?
Post by: V8Cowboy on 06 August 2013, 11:41:28

Hi,

As you will probably know there are 2 sensors on the 3.2, one for regulation and one behind the cat for monitoring, for each bank. I was wondering if the sensors pre/post cat are technically the same, except for the cable length? I'm asking because I need one of the post cat sensors and I once ordered Bosch pre cat sensors in an UK-webshop for the half of the price than I could get it anywhere else here. But this shop only has the pre cat sensors and if they are technically the same, I would be happy and could order one. :)

Many thanks in advance.

Greetings from Austria and from an office with 35 degrees... :s

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: zirk on 06 August 2013, 11:47:19

Has the Sensor failed, or is it just throwing EML and fault codes which is normally down to makes of different fuel on the 3.2's.

Do you know about the Mod thats recommended here of moving the sensors back.?

And yes greetings from London, think we hit 33 degress one day last week, never mind soon be Christmas.

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: V8Cowboy on 06 August 2013, 12:42:29

Yes, I got EML, but because of faulty sensor heating. I measured infinite resistance of this sensor's heating while the other one had the supposed.. I don't know.. 40-50 Ohms? According to the values of the official fault code procedure. So im 99,99% sure it's really a simple sensor change.

I moved the lambdas already some years ago, thanks to this forum :) Nobody on the continent had a clue about it, might be because there are far less 3.2 or 2.6 running on the streets here.

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: zirk on 06 August 2013, 12:46:37

OK, was just checking on the O2 Mod, in that case I cant answer your question, they are both the same type of sensor and fitments but different part numbers from Pre and Post from memory  :-\

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: zirk on 06 August 2013, 12:54:57

I suppose you could check one of those Universal Lambda sensors Online, you know where they supply the sensor and crimp plugs so you can fit your original plug and see if the type and part numbers are the same, not suggesting you use them of course, but mite give a idea on compatibility.

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: Kevin Wood on 06 August 2013, 13:44:36

I believe the only difference between pre and post cat sensors is the length of the wiring harness.

I've certainly swapped them for diagnostic purposes and they behave the same.

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: V8Cowboy on 06 August 2013, 13:45:50

 :y That was a good idea! I wonder why this didn't come to my mind, now I honestly have doubts about my intelligence. Let's blame it on the heat, ok? :)

I checked two shops and the universal sensor is listed for both pre and post position. Therefore, many thanks, I think my question is now well answered.  ;)

@Kevin: thx to you too!

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: biggriffin on 06 August 2013, 14:37:13

Silly question time  are 3.0L cats and 3.2 cats the same i.e 3 wire?

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: zirk on 06 August 2013, 17:10:39

Quote from: biggriffin on 06 August 2013, 14:37:13

Silly question time  are 3.0L cats and 3.2 cats the same i.e 3 wire?

No 3.2 are 4 wire from memory, although the 4th wire is just another earth return, fairly sure there made from a different sensor material as well.

Title: Re: Pre cat / post cat o2 sensor technically the same?
Post by: biggriffin on 06 August 2013, 21:06:47

Dam :( cant use the 2 nearly new lamdas ive got then. :'(