Failed Emissions Tests - Help

[Scoobz1]

Any clues as to what the following readings may indicate (S1 Elise fairly standard) from a failed emissions tests . I can get the CO to pass (last result) or the Lambda 2nd result but not both to go through together !

My results (sorry about the columns but when I submit it - it looks different to how it appeared initially- 3 perfectly spaced columns)

CO HC Lambda
.488; 38; 1.055
.446: 30; 1.03
.217; 90 ; 1.099
.223; 89; 1.098
.209; 71; 1.103
.197 ; 71; 1.109

Video of 1st result above - As the revs went up (3300 to 3500) the CO went up, HC went up and Lambda went up see below

CO HC Lambda
.488 38 1.055 (initial value)
563 45 1.059 (increases to )

Any thoughts / theories greatly appreciated as it would be good to have some educated idea where to start

Thanks

Scoobz

Edited by Scoobz1 on Thursday 29th April 13:58

Edited by Scoobz1 on Thursday 29th April 14:00

[Megaflow]

What did you do to bring down the CO?

There is not a huge amount to go on from the OP, but given CO, HC and lambda are all high, it seems to me like it is running rich, assuming standard map and sensors I’d be looking for a light misfire, plugs or HT leads as a starting point.

[LimSlip]

The high lambda value indicates excess oxygen in the exhaust, and the CO is indicating too much fuel. This apparently contradictory situation can occur when you have an exhaust leak upstream of the oxygen sensor, air gets pulled in and the ECU interprets the higher oxygen level as a weak mixture and adds more fuel.

[Scoobz1]

Ordered a new Lambada sensor which I will fit and also check for leaks at the time ...

Definitely running a bit rich as I can smell it and have note the contradiction between this and the Lambda readings ....

Thanks

Scoobz

[stevemcs]

Any exhaust leaks ?

[E-bmw]

Scoobz1 said:

Ordered a new Lambada sensor

Does that detect when someone is dancing near the car then?

[SlimJim16v]

E-bmw said:

Does that detect when someone is dancing near the car then?