Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Omega Nige on 22 May 2023, 13:01:19

Title: O2 sensor
Post by: Omega Nige on 22 May 2023, 13:01:19
Hi, on my 3.2 I keep getting a warning light o2 bank 2 sensor 1. Where is it on the exhaust? I clear it and it comes back on when crusing at about 40mph.
Title: Re: O2 sensor
Post by: TheBoy on 22 May 2023, 13:07:27
Pretty standard for either Bank1 Sensor 2, or Bank 2 Sensor 2 to do this on 2.6/3.2.

Solution is to move the sensor from its current location between the starting cat and the main cat, to after the main cat.  This is achieved by welding in a new boss into the cat section, after the main cat, and moving the sensor, and plugging the original sensor hole.  Bosses with plugs are only a few quid, though its possible you will struggle to remove the old sensor, so might need to abandon that in place, and put a new one in the new boss.

Then reset the codes one last time, and problem solved. Forever.
Title: Re: O2 sensor
Post by: Doctor Gollum on 22 May 2023, 15:25:33
Hi, on my 3.2 I keep getting a warning light o2 bank 2 sensor 1. Where is it on the exhaust? I clear it and it comes back on when crusing at about 40mph.
Use a tank of Shell V power, a couple of cans of Wynns fuel treatment and drive it like you stole it. If you get over 240 miles out of the tank, then you're simply not driving it hard enough.

Driving in top at 40mph is guaranteed to put the light on.

It needs to be driven firmly to keep the P0420/0430 at bay. Those codes are factory fitted, so they will appear periodically, but less if you actually drive the car and more if you pootle everywhere.
Title: Re: O2 sensor
Post by: TheBoy on 22 May 2023, 15:54:59
That can help hold them at bay for a bit, but ultimately, its the number of cold starts that kills the starting cat, causing the light.

Hence the recommendation to move the sensors, which is a total cure.
Title: Re: O2 sensor
Post by: Doctor Gollum on 22 May 2023, 19:45:36
Never bothered on my ex plod, but that was never cold. Or driven particularly gently >:D
Title: Re: O2 sensor
Post by: dave the builder on 22 May 2023, 22:08:24
 ::)


Hi, on my 3.2 I keep getting a warning light o2 bank 2 sensor 1. Where is it on the exhaust? I clear it and it comes back on when crusing at about 40mph.

"bank 2 sensor 1 " is pre cat sensor on bank 2  :-\
not post cat "catalyst efficiency" problems AKA bank 1 or 2 sensor 2   
new O2  sensor ,pre cat ,bank 2  :)
Is "bank 2 " the 2.4.6 side  :-\
Title: Re: O2 sensor
Post by: Doctor Gollum on 22 May 2023, 22:14:56
Yup 135=Bank1 ;)
Title: Re: O2 sensor
Post by: dave the builder on 22 May 2023, 22:33:06
Yup 135=Bank1 ;)
:y

so, the O2 sensor on the near side (UK car/ left)  BEFORE the pre cat ( top of downpipe) needs replacing
assuming the OP has read the codes correctly  :-X

not much room to work  :(
Title: Re: O2 sensor
Post by: Doctor Gollum on 23 May 2023, 04:25:32
Leave the sensor in and fit a new one down stream. If you cba to drive the car rather than pootle it.
Title: Re: O2 sensor
Post by: TheBoy on 23 May 2023, 12:39:33
Ah, I read Bank 1 Sensor 2 for some reason, lol.  Dyslexia rules ;D

What is the actual code, is it could be something else.  Note, Sesnor 1 cannot be moved.
Title: Re: O2 sensor
Post by: Migalot on 23 May 2023, 17:33:37
For what it's worth, i had the same Bank 2 Sensor 1 fault and it took weeks before JamesV6CDX discovered it was actually Sensor 2 that was duff. The engine ECU gets it's Sensor 1 information via Sensor 2, so if 2 is bad, it can incorrectly report 1.

Car ran like a pig until the problem was sorted. Runs beautifully now. 
Title: Re: O2 sensor
Post by: TheBoy on 24 May 2023, 09:11:16
For what it's worth, i had the same Bank 2 Sensor 1 fault and it took weeks before JamesV6CDX discovered it was actually Sensor 2 that was duff. The engine ECU gets it's Sensor 1 information via Sensor 2, so if 2 is bad, it can incorrectly report 1.

Car ran like a pig until the problem was sorted. Runs beautifully now.
I'd say it was more likely that their connectors had been crossed.   S2 has no impact on engine metrics, its just an emissions test.  S1 controls the fuelling.
Title: Re: O2 sensor
Post by: deviator on 24 May 2023, 10:32:31
I used to use lambda spacers on the 2.6 Vectra. They took the tip out of the flow and stopped the codes.