Technical Running lean

[shaun]

Hi, I have just taken my 98 barchetta for MOT and it has failed on emissions. I was told it was running lean. I have previously cleaned the Maf Icv and throttle body. New fuel and air filters and plugs.Any ideals what I can do next

Thanks Shaun

 

[jackwhoo]

Post pic of emission fail sheet.
I expect it has failed on lambda value, if so possible leaks in exhaust the cause.

 

[shaun]

Thanks Jack

 

[jackwhoo]

Fix any exhaust leaks.
If twin tail pipes ask tester to put a rag in the tail pipe that doesn't have probe in it

 

[shaun]

OK thanks Jack

 

[jackwhoo]

The lambda result from testing machine is not a reading of how well engine is running. I think it's to ensure probe is not being misused to fool result- I'm not entirely sure. If you find a good explanation online or elsewhere please post it(-: