Hello all,

Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto it 
gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at 
2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when switching 
from gas to petrol and 5% when going back to gas but soon settles to the low 
levels again in both directions. I gives very poor mileage on gas 15 mpg at 
very best, and it struggles to get 20mpg on petrol around town. It also 
intermittently cuts on tickover seems to be something to do with the idle 
bypass air valve.

Any comments?

George

"George Gosbee"  wrote in message
news:J0tMe.7481$Wq4.6278@fe1.news.blueyonder.co.uk...

> Hello all,
>
> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto it
> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at
> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when
switching
> from gas to petrol and 5% when going back to gas but soon settles to the
low
> levels again in both directions. I gives very poor mileage on gas 15 mpg
at
> very best, and it struggles to get 20mpg on petrol around town. It also
> intermittently cuts on tickover seems to be something to do with the idle
> bypass air valve.



The Gunsons 'professional' CO meter is an infrared type rather than a gas
analysis tool and you wont get anything meaningful from it when using it on
an LPG system. It actually measures CO2 and HC and then calculates CO from
what I remember. (or something like that)

Tim..

"Tim.."  wrote in message 
news:dduru5$nt2$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...

>
> "George Gosbee"  wrote in message
> news:J0tMe.7481$Wq4.6278@fe1.news.blueyonder.co.uk...
>> Hello all,
>>
>> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto it
>> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at
>> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when
> switching
>> from gas to petrol and 5% when going back to gas but soon settles to the
> low
>> levels again in both directions. I gives very poor mileage on gas 15 mpg
> at
>> very best, and it struggles to get 20mpg on petrol around town. It also
>> intermittently cuts on tickover seems to be something to do with the idle
>> bypass air valve.
>
>
> The Gunsons 'professional' CO meter is an infrared type rather than a gas
> analysis tool and you wont get anything meaningful from it when using it 
> on
> an LPG system. It actually measures CO2 and HC and then calculates CO from
> what I remember. (or something like that)
>
> Tim..
>
>

Thanks Tim,

Its a hot wire type, does this make any difference?

George.

"George Gosbee"  wrote in message 
news:WKMMe.10918$Wq4.4534@fe1.news.blueyonder.co.uk...

>
> "Tim.."  wrote in message 
> news:dduru5$nt2$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...
>>
>> "George Gosbee"  wrote in message
>> news:J0tMe.7481$Wq4.6278@fe1.news.blueyonder.co.uk...
>>> Hello all,
>>>
>>> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto it
>>> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at
>>> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when
>> switching
>>> from gas to petrol and 5% when going back to gas but soon settles to the
>> low
>>> levels again in both directions. I gives very poor mileage on gas 15 mpg
>> at
>>> very best, and it struggles to get 20mpg on petrol around town. It also
>>> intermittently cuts on tickover seems to be something to do with the 
>>> idle
>>> bypass air valve.
>>
>>
>> The Gunsons 'professional' CO meter is an infrared type rather than a gas
>> analysis tool and you wont get anything meaningful from it when using it 
>> on
>> an LPG system. It actually measures CO2 and HC and then calculates CO 
>> from
>> what I remember. (or something like that)
>>
>> Tim..
>>
>>
> Thanks Tim,
>
> Its a hot wire type, does this make any difference?
>
> George.
>

The XM service manual states <0.5% CO at idle.

George.

On Wed, 17 Aug 2005 21:04:06 +0100, George Gosbee  
 wrote:


>
> "Tim.."  wrote in message
> news:dduru5$nt2$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...
>>
>> "George Gosbee"  wrote in message
>> news:J0tMe.7481$Wq4.6278@fe1.news.blueyonder.co.uk...
>>> Hello all,
>>>
>>> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto  
>>> it
>>> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at
>>> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when
>> switching
>>> from gas to petrol and 5% when going back to gas but soon settles to  
>>> the
>> low
>>> levels again in both directions. I gives very poor mileage on gas 15  
>>> mpg
>> at
>>> very best, and it struggles to get 20mpg on petrol around town. It also
>>> intermittently cuts on tickover seems to be something to do with the  
>>> idle
>>> bypass air valve.
>>
>>
>> The Gunsons 'professional' CO meter is an infrared type rather than a  
>> gas
>> analysis tool and you wont get anything meaningful from it when using it
>> on
>> an LPG system. It actually measures CO2 and HC and then calculates CO  
>> from
>> what I remember. (or something like that)
>>
>> Tim..
>>
>>
> Thanks Tim,
>
> Its a hot wire type, does this make any difference?
>
> George.
>
>


It measures thermal conductivity, not CO directly , so it's confused by  
different fuel types. Check the usual suspects such as air leaks on the  
inlet side & IIRC Draper sell a very cheap fault code reader for XMs.


-- 
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

"Duncanwood"  wrote in message 
news:op.svn6asi34wom51@amy...

> On Wed, 17 Aug 2005 21:04:06 +0100, George Gosbee 
>  wrote:
>
>>
>> "Tim.."  wrote in message
>> news:dduru5$nt2$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com...
>>>
>>> "George Gosbee"  wrote in message
>>> news:J0tMe.7481$Wq4.6278@fe1.news.blueyonder.co.uk...
>>>> Hello all,
>>>>
>>>> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto 
>>>> it
>>>> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at
>>>> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when
>>> switching
>>>> from gas to petrol and 5% when going back to gas but soon settles to 
>>>> the
>>> low
>>>> levels again in both directions. I gives very poor mileage on gas 15 
>>>> mpg
>>> at
>>>> very best, and it struggles to get 20mpg on petrol around town. It also
>>>> intermittently cuts on tickover seems to be something to do with the 
>>>> idle
>>>> bypass air valve.
>>>
>>>
>>> The Gunsons 'professional' CO meter is an infrared type rather than a 
>>> gas
>>> analysis tool and you wont get anything meaningful from it when using it
>>> on
>>> an LPG system. It actually measures CO2 and HC and then calculates CO 
>>> from
>>> what I remember. (or something like that)
>>>
>>> Tim..
>>>
>>>
>> Thanks Tim,
>>
>> Its a hot wire type, does this make any difference?
>>
>> George.
>>
>>
>
> It measures thermal conductivity, not CO directly , so it's confused by 
> different fuel types. Check the usual suspects such as air leaks on the 
> inlet side & IIRC Draper sell a very cheap fault code reader for XMs.
>

I have a Sykes fault code reader and it shows no faults since I changed the 
lambda sensor. This was done as the fault regularly came up CO reading out 
of range.

George.

George Gosbee (georgegosbee@blueyonder.co.uk) gurgled happily, sounding
much like they were saying : 


>> IIRC Draper sell a very cheap fault code reader for XMs. 

> I have a Sykes fault code reader and it shows no faults since I
> changed the lambda sensor.


George...

IIRC, yours is a late s2 24v?

Does the Sykes reader work on it? Have you tried the Draper? I've got a 
Draper, and have had no joy on my s2 TCT.

"Adrian"  wrote in message
news:Xns96B5DD82B68DDadrianachapmanfreeis@204.153.244.170...

> George Gosbee (georgegosbee@blueyonder.co.uk) gurgled happily, sounding
> much like they were saying :
>
>>> IIRC Draper sell a very cheap fault code reader for XMs.
>
>> I have a Sykes fault code reader and it shows no faults since I
>> changed the lambda sensor.
>
> George...
>
> IIRC, yours is a late s2 24v?
>
> Does the Sykes reader work on it? Have you tried the Draper? I've got a
> Draper, and have had no joy on my s2 TCT.


Yes no trouble at all, gives a lot of readings as well, like injector pulse
time or exhaust sensor mVolts.

What's your location? may be able to give you a loan. Only got S2 30pin lead
and not the S1 2pin.

George.

George Gosbee (georgegosbee@blueyonder.co.uk) gurgled happily, sounding
much like they were saying : 


>> IIRC, yours is a late s2 24v?
>>
>> Does the Sykes reader work on it? Have you tried the Draper? I've got
>> a Draper, and have had no joy on my s2 TCT.

> Yes no trouble at all, gives a lot of readings as well, like injector
> pulse time or exhaust sensor mVolts.
> 
> What's your location?


NW M25... Nowhere near you.


> may be able to give you a loan. Only got S2 30pin lead


Ooooh!

"Adrian"  wrote in message 
news:Xns96B5E392DA81Dadrianachapmanfreeis@204.153.244.170...

> George Gosbee (georgegosbee@blueyonder.co.uk) gurgled happily, sounding
> much like they were saying :
>
>>> IIRC, yours is a late s2 24v?
>>>
>>> Does the Sykes reader work on it? Have you tried the Draper? I've got
>>> a Draper, and have had no joy on my s2 TCT.
>
>> Yes no trouble at all, gives a lot of readings as well, like injector
>> pulse time or exhaust sensor mVolts.
>>
>> What's your location?
>
> NW M25... Nowhere near you.
>
>> may be able to give you a loan. Only got S2 30pin lead
>
> Ooooh!


Coming down to Oxford for the weekend soon 2-3 weeks (awaiting the wife,s 
brother to become a father for the first time.

George.

George Gosbee (georgegosbee@blueyonder.co.uk) gurgled happily, sounding
much like they were saying : 


> Coming down to Oxford for the weekend soon 2-3 weeks 


My email works. Does it just do engine management codes, or does it do 
climate, too?


> (awaiting the
> wife,s brother to become a father for the first time.


Commiserations... <g>

> Just put a Gunsons professional CO meter on my Citroen XM 3.0 V6 auto it 
> gave some very low readings 0.5% tickover on gas 0.01 to minus 0.09 at 
> 2000rpm and only +0.1 approx on petrol. The CO goes up to 8% when 
> switching from gas to petrol and 5% when going back to gas but soon 
> settles to the low levels again in both directions. I gives very poor 
> mileage on gas 15 mpg at very best, and it struggles to get 20mpg on 
> petrol around town. It also intermittently cuts on tickover seems to be 
> something to do with the idle bypass air valve.


It's a big heavy car.

It's got a 3 litre V6 engine.

It's got an automatic gearbox.

Exactly what sort of economy were you expecting around town? 20mpg seems 
about right, in fact it's bloody good if it does a fair few short journeys. 
A bit less on gas is par for the course - I know that depending on the type 
of use, using gas is either about as economical, or a fair bit less 
economical than using petrol.

In short, there's nothing wrong with your car.

-- 
Peter

"You're not a real UKRCMer until you've had your big end bearings go."