Elan scan reading for Air/Fuel ratio

[sponcom]

My elan has jsut failed it's MOT of slightly high CO2 emmisions 3.7 when the limit was 3.5%. hydrocarbons were only a tenth of what is permitted so that was fine.

Lambda sensor at idel is reading 2V in elanscan which I think is within normal realms but the air fuel ration reads 14. I would have thought that 14.7 was the ideal (a Lambda of 1) so is it running a bit rich?
Could anyone post what they see their air fuel reading on elan scan at idle please? Is it any different to mine.

BTW it is a non cat engine.

Thanks

[GeoffSmith]

I don't think you have an O2 sensor so the steady 2V output is the setting of the CO pot and the nominal A/F ratio for open loop cars is 14, so everything appears correct. You need to get the garage to adjust the CO pot to get the emissions correct. Looks like there is nothing on the Wiki yet but ESM's website gives a link to manual EMK.3-E and if you do a search for "emission pot" there are plenty of threads about it.

[sponcom]

Thanks Geoff,

of course there is no Lambda sensor doh! Now I know why the sensor values aren't changing!

The MOT man can adjust my memcal pot it's just that he couldn't find it when I took it in!

Cheers

Paul

[John_W]

Paul,
Do you know what chip you have?
The earlier 9929 & 9239 chips were subject to an upgrade (exchange) by Lotus to a 9930 chip to allow more adjustment of CO to meet MOT emissions. If you still have an older chip, just adjusting the CO pot may not be enough to fix the problem. But it's a good place to start. Also make sure your base timing is OK, as well as plugs & plug gaps.
John