Failed NCT on emission

[shan001]

Hi,

Please help me with this issue on my MX5.

I have a mk1 NA Eunos from 1992.

It has failed emission test on the NCT, and it has failed by a lot

The lambda sensor has been changed on the car. The car does not have steady idle, in particular when egine is cold, it keeps stop running.
My mechanic refers to an Air Fuel Ratio sensor. Is there such a thing in this car, can I buy it from your site if it exists.
What else could cause the problem? Any help welcome, thanks.

[MX5Spares]

We have loads of mx5 part sin Dublin 086 8226506 but without confirming exactly what is wrong you could be going back to NCT for the next year !! Some have air flow sensors ,some have MAF sensor ?? early and late type and 1.6 or 1.8 but we have them all.

[Steve]

Check your air intake pipe post-air flow meter for leaks. Any hissing around the intake manifold? Does it idle ok?
Also, this is worth a read re additives :
viewtopic.php?f=3&t=6382&start=30

[ger]

I had similar problems to this turned out to be my o2 sensor and a hole in my exhaust, while trying to locate the problem I did clean the airflow meter and throttle body and intake manifold. One other thing that can cause this is the temp sensor http://www.mx5parts.co.uk/sensor-water- ... p-862.html at the back of the engine or a faulty airflow meter. My nct went from 8.5% CO to 0.37% CO.

[shan001]

Many thanks for the comments, mine is 0.755, so have a lot to do I'd say.
If the weather stays I'll get my hands dirty tomorrow