Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: haj on 21 January 2008, 14:53:17

Title: CO woe!
Post by: haj on 21 January 2008, 14:53:17
Have high co on idle and rising on accelaration.so suspected lambda sensor

tested sensor heater resistance 5.3 ohms.tested signal hardly a reading on meter (set to 2 volt scale.So am pretty certain it is at fault.

Thing is how do i tell if it is titania or zirconia sensor?

Also are gendan / lambapower sensors worth purchasing for me mig.

Main stealer wants £120 +vat.

Local factors want £70 for a universal lambda sensor.Don't really fancy fitting one of these as i think they may cause problems later on.
Title: Re: CO woe!
Post by: Kevin Wood on 21 January 2008, 14:59:11
Before you jump, it would be a good idea to check the ECU for trouble codes just in case it's something else (could be faulty coolant temperature sensor running the engine rich, for example).

A failed Lambda sensor would certainly light the engine management light and generate trouble codes so if this hasn't happened I would be suspicious. (Does the light itself work, for example).

Kevin
Title: Re: CO woe!
Post by: cem_devecioglu on 21 January 2008, 15:02:23
Hi
before changing lambda sensors be sure you dont have air leaks..

Many factors on the engine can change exhaust mixture..Such as a

faulty MAF..

Try reading stored codes with a paperclip test first..if you got EML..

Heres also a link to lambda sensors:

http://www.lambdapower.co.uk/partsearch/az2.asp?var_Manufacturer=Vauxhall/Opel&var_Model=Omega

Title: Re: CO woe!
Post by: cem_devecioglu on 21 January 2008, 15:03:01
Quote
Before you jump, it would be a good idea to check the ECU for trouble codes just in case it's something else (could be faulty coolant temperature sensor running the engine rich, for example).

A failed Lambda sensor would certainly light the engine management light and generate trouble codes so if this hasn't happened I would be suspicious. (Does the light itself work, for example).

Kevin


You are much faster  :y
Title: Re: CO woe!
Post by: haj on 21 January 2008, 15:03:15
Yep eml works ok.

Thing is i disconnected the plug to the sensor and ran the engine but no fault light showed up.
Title: Re: CO woe!
Post by: Craig_R on 21 January 2008, 15:17:12
If you do need to change your lambda have a look for NGK lambda's at your local car parts place Vauxhalls lambda's are made by NGK/NTK I got mine for 80 quid
Title: Re: CO woe!
Post by: Kevin Wood on 21 January 2008, 15:44:27
Quote
Yep eml works ok.

Thing is i disconnected the plug to the sensor and ran the engine but no fault light showed up.

It may not have shown a problem until the engine got fully up to temperature. IIRC, the early ECUs don't drive the Lambda heater so they would not detect a break in this circuit. This backs up my thoughts that it could be something like a coolant temperature sensor, TBH. If the car was driven with a faulty Lambda it should have generated codes.

I would do a paper clip test on the car and see if any stored codes are reported before spending any money.

Kevin


Title: Re: CO woe!
Post by: haj on 21 January 2008, 15:52:03
Quote
Quote
Yep eml works ok.

Thing is i disconnected the plug to the sensor and ran the engine but no fault light showed up.

It may not have shown a problem until the engine got fully up to temperature. IIRC, the early ECUs don't drive the Lambda heater so they would not detect a break in this circuit. This backs up my thoughts that it could be something like a coolant temperature sensor, TBH. If the car was driven with a faulty Lambda it should have generated codes.

I would do a paper clip test on the car and see if any stored codes are reported before spending any money.

Kevin


righto,i'll pop into work tonight,they have an underground car park so no rolling about in the wet,and try paper clip test see what i get.I'll also recheck sensor volts just incase croc clip was not on cable properly.

Thanks ,shall let you know my findings
Title: Re: CO woe!
Post by: Kevin Wood on 21 January 2008, 16:48:50
Just to say, make sure the car is fully up to temperature (wait until cooling fan kicks in), use a digital multimeter and you should see the lambda sensor voltage varying between about 0 and 5 volts (I believe the 4 pots have 5v output). Blip the throttle a few times if it initially doesn't appear to do anything and then try holding the revs at 2500 RPM or so for a minute or so.

However, if you don't see a signal, it's no necessarily the sensor, because if you've got overfuelling due to another fault it could be that the sensor will just be indicating "rich" all the time.

The paperclip test might tell us something, though.

Kevin
Title: Re: CO woe!
Post by: Craig_R on 21 January 2008, 19:14:08
If I remember rightly you cant measure a 5volt lambda the way you can with a 1volt lambda 5 volt lambda works on resistance Ohms
Title: Re: CO woe!
Post by: hol666 on 21 January 2008, 19:18:38
Might be worth changing the ecu temperature sensor on the back of the block, this is not the one for the dash gauge though! Not expensive @ £8 from vxl, sadly not from a factor though, good luck  :y