Omega Owners Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Please play nicely.  No one wants to listen/read a keyboard warriors rants....

Pages: [1] 2  All   Go Down

Author Topic: The 3.2/2.6 O2 sensor mystery.  (Read 2774 times)

0 Members and 1 Guest are viewing this topic.

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
The 3.2/2.6 O2 sensor mystery.
« on: 03 January 2008, 08:45:29 »

OK

Done some research and asked some people who work with Vx's on a daily basis (experts not mechanics!).

First, to clear things up......the value from the second 02 sensor should not change.....it should be constant as suspected.

Right, the setup on these units is that of a mixture regulation sensor followed by a small pre-cat, a cat check sensor and then the main cat.

One of the guys contacted has tried cleaning the 02 sensors on these and it made no major difference.

What we suspect is that the pre-cat is dropping in performance and this is being detected by the cat check sensor but, emissions are not affected at all thanks to the main cat being OK.

The suspicion is that the pre-cat is to small hence why its more prevalent on the 3.2 than the 2.6 (bigger engine more gas output).

This would also offer an explanation as to why using better fuels can help as these are likely to have a cleaning affect on the pre-cat.

The ideal fix would be for Vx to modify the engine software so its not nearly as sensitive to what is not a major problem.

Another possible is to run a good quality treatment through the fuel system with good cat cleaning properties to try and restore some of the pre-cat efficiency.....if such thing exists!
« Last Edit: 03 January 2008, 08:46:25 by Mark »
Logged

VXL V6

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Warwickshire
  • Posts: 9875
    • 530D M Sport, Elite 3.2
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #1 on: 03 January 2008, 08:58:47 »

Great work Mark.

I've heard 'cataclean' is good.

Thanks!  :y
« Last Edit: 03 January 2008, 09:00:43 by VXL_V6 »
Logged

MikeDundee

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Costa Del Peckham
  • Posts: 9370
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #2 on: 03 January 2008, 09:01:15 »

I have just replaced all my sensors, won't know whether that solves my problem until I get the EML reset. So have 4 very dirty sensors sitting in boxes in the kitchen ;D
Logged

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #3 on: 03 January 2008, 09:04:43 »

Quote
Great work Mark.

I've heard 'cataclean' is good.

Thanks!  :y

I also have heard good reports about cataclean....but if you use it remember that the Omega has a bloody big fuel tank so you need to take care on your dosing levels.
Logged

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #4 on: 03 January 2008, 09:05:08 »

Quote
I have just replaced all my sensors, won't know whether that solves my problem until I get the EML reset. So have 4 very dirty sensors sitting in boxes in the kitchen ;D


These we can clean.....
Logged

MikeDundee

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Costa Del Peckham
  • Posts: 9370
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #5 on: 03 January 2008, 09:10:48 »

Quote
Quote
I have just replaced all my sensors, won't know whether that solves my problem until I get the EML reset. So have 4 very dirty sensors sitting in boxes in the kitchen ;D


These we can clean.....

Some carb cleaner then?
Logged

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #6 on: 03 January 2008, 09:12:48 »

No....a special cleaner in an ultrasonic bath.
Logged

MikeDundee

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Costa Del Peckham
  • Posts: 9370
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #7 on: 03 January 2008, 09:16:51 »

Quote
No....a special cleaner in an ultrasonic bath.

Really?,............ you winding me up ;D.........I beleive you Mark ;D.........never knew about ultrasonic baths, very interesting :-/
« Last Edit: 03 January 2008, 09:22:55 by mickdundee »
Logged

Kevin Wood

  • Global Moderator
  • *****
  • Offline Offline
  • Gender: Male
  • Alton, Hampshire
  • Posts: 36419
    • Jaguar XE 25t, Westfield
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #8 on: 03 January 2008, 09:18:45 »

Thanks for the information. Interesting... I guess the pre-cats are the devices in the elbow of the exhaust where it turns rearwards below the manifold? Always wondered what was in them, and why the post cat sensors weren't behind what looked like the cats :-/

Given that MOT emissions are still fine without them, and that their only purpose appears to be to drive  the emissions light, the bodger in me wonders if the signal from the post cat sensors can be spoofed to keep the ECU happy? After all, I'll replace the cats when the emissions are no longer MOT compliant, not when a light on the dash tells me, thanks.

Kevin
Logged
Tech2 services currently available. See TheBoy's price list: http://theboy.omegaowners.com/

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #9 on: 03 January 2008, 09:30:00 »

Quote
Thanks for the information. Interesting... I guess the pre-cats are the devices in the elbow of the exhaust where it turns rearwards below the manifold? Always wondered what was in them, and why the post cat sensors weren't behind what looked like the cats :-/

Given that MOT emissions are still fine without them, and that their only purpose appears to be to drive  the emissions light, the bodger in me wonders if the signal from the post cat sensors can be spoofed to keep the ECU happy? After all, I'll replace the cats when the emissions are no longer MOT compliant, not when a light on the dash tells me, thanks.

Kevin

Yes, the pre-cats are the part mounted in the elbow with the heat shield around it.

I am sure the use of a few resistors or resistor-zener setup would do a nice job of keeping the ECU quiet.
Logged

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #10 on: 03 January 2008, 09:32:16 »

Quote
Quote
No....a special cleaner in an ultrasonic bath.

Really?,............ you winding me up ;D.........I believe you Mark ;D.........never knew about ultrasonic baths, very interesting :-/


Ow yes....they are often used for cleaning, excellent for jewelery, cds, watch straps etc.
Logged

MikeDundee

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Costa Del Peckham
  • Posts: 9370
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #11 on: 03 January 2008, 09:38:53 »

Quote
Quote
Quote
No....a special cleaner in an ultrasonic bath.

Really?,............ you winding me up ;D.........I believe you Mark ;D.........never knew about ultrasonic baths, very interesting :-/


Ow yes....they are often used for cleaning, excellent for jewelery, cds, watch straps etc.

Obviously need to send off to a specialist then for cleaning?
Logged

MikeDundee

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • Costa Del Peckham
  • Posts: 9370
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #12 on: 03 January 2008, 09:39:55 »

Or buy one of these?

http://www.bestultrasonic.com/
Logged

Golfbuddy

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Cornwall
  • Posts: 4151
  • I'm On An Economy Drive
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #13 on: 03 January 2008, 09:49:57 »

As most of you know, I don't know a lot about engines and how they work. I was interested though to read the article in the following link regarding engine cleaners and treatments.

I make no comments as to it's validity, I will leave that to cleverer men than I, but it does make interesting reading.

LINK
Logged
[size=24]        [/size][/b]

Marks DTM Calib

  • Administrator
  • *****
  • Offline Offline
  • Gender: Male
  • West Bridgford
  • Posts: 34026
  • Git!
    • View Profile
Re: The 3.2/2.6 O2 sensor mystery.
« Reply #14 on: 03 January 2008, 09:58:28 »

Quote
As most of you know, I don't know a lot about engines and how they work. I was interested though to read the article in the following link regarding engine cleaners and treatments.

I make no comments as to it's validity, I will leave that to cleverer men than I, but it does make interesting reading.

LINK


Your right.....he knows nothing (but doesn't claim to!)

Quote
Anything strong enough to dissolve years of deposits in just a few seconds may well also attack sensitive components such as manifold pressure sensors, which are not generally designed or tested to be resistant to such cleaning products

No chance of a cleaner getting anywhere near a MAP sensor.....its a fuel additive and you dont get fuel back up the inlet. And even then, MAP sensors are on a stub so no air flow.

We are talking about a one off dose here to try to resolve a problem on higher mileage cars as an alternative to spending 1000 quid on cats.....

Logged
Pages: [1] 2  All   Go Up
 

Page created in 0.02 seconds with 16 queries.