CO reading ??

Well, first off a Gunsons meter is not the most accurate there is - I know I have used them. It might be an indication of something wrong, but don't use it to make any settings changes.

Your MPG isn't all that bad for a 3.0 V6 auto on a car that size. Many factors might affect that - general condition of engine, air/con being used, drive with windows open, tyre pressures, the way you drive, driving pattern etc. If you have all of those on the bad side, then you will lose a lot of MPG. For example, driving with a window open uses as much extra fuel as using the air/con - about 10% as a rule.

If you could get that up to the mid 20's MPG I think you'd consider that good.

The stalling and consumption issue might be an indication of an air leak somewhere. Check all vacuum tubes, and air intake ducting. Failing that you might need to consider manifold gaskets and such like too. A piece of rubber hose held to the ear, while probing around the engine, can often reveal an air leak (you'll hear the hissing).

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

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 ( snipped-for-privacy@blueyonder.co.uk) gurgled happily, sounding much like they were saying :

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 ( snipped-for-privacy@blueyonder.co.uk) gurgled happily, sounding much like they were saying :

NW M25... Nowhere near you.

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 ( snipped-for-privacy@blueyonder.co.uk) gurgled happily, sounding much like they were saying :

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

Commiserations...

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.