Emissions issue-Failed MOT

[mshariq4]

Hey Guys

My 1994 NSX failed emission during MOT test. The CO is 1.37% , HC 1944 ppm and Lambda 1.06. Is there any workshop around Leicester which can help.

Thanks

Shariq

 

[Honcho]

Not sure about the UK cars but 1994 should be OBD-I, so things to look at are:

O2 sensors
Spark plugs
Coils
Fuel injectors
Cats

Are you getting any trouble codes?

@Kaz-kzukNA1

 

[Old Guy]

If you are looking for a shop in the UK you might get more responses by posting on the NSX club of GB forum

NSXCB Forums - Home

Home

www.nsxcb.co.uk

As an observation, your HC seems grossly high. If the car is a 1994 the catalytic converters may have reached their best before date. Other potential guilty parties include
- leaking fuel injectors
- a dirty intake air temperature sensor
- tired O2 sensor(s)
- fuel pressure out of spec

Use the diagnostic test connector to retrieve any stored error codes. Those might give you a hint as to what might be going on.

 

[NSXGB]

My cats are 30 years old and struggle slightly on the MoT test. The way to get it through is to take the car for a hack up the motorway and then straight to the testing station while the cats are red hot still. Get it tested straight away and ill bet you it passes.

 

[Old Guy]

Hot cats on the pre 2000 cars that don't have the aux air pump will definitely help. But, his HC numbers look way beyond 'struggling slightly'. His numbers looked like the cats nipped out to the pub around the corner for a pint and never made it back.

 

[MJK]

Not sure about the UK cars but 1994 should be OBD-I, so things to look at are:

O2 sensors
Spark plugs
Coils
Fuel injectors
Cats

Are you getting any trouble codes?

@Kaz-kzukNA1

Agree. Cleaning the IAT is also a good idea.