Failed MOT on lambda readings

[k7lsy]

Hi guys,

First time car has failed MOT on emissions - it failed on the lambda readings.

MOT reading:
CO 0.17% pass
HC 28ppm pass
Lambda 1.08 fail ... i think max is 1.03

Any thoughts on what may need replaced?

Thanks in advance,
Kenny

[D_G]

Could be an exhaust leak with those readings. Looks like too much air so unlikely to be the sensors as they normally cause overfuelling. Easy to check them though. Also check for a vacuum leak on the engine.

HTH
Dave

[jdearden]

If there that close. I would run it low on petrol and put some injector cleaner in it. Get it hot and retest it. Should then go through.

[Gadgeroonie]

try fitting a new lambda sensor

[Naso Grande]

Gadgeroonie said:

try fitting a new lambda sensor

I've just bought 2 Lambda Sensors today. Any tips on how to get access to change the front one? Is it possible to get to it by removing the panels in the offside rear wheel arch and to come in underneath the a/c compressor?

Both of mine appear to behave normally on the diagnostics but ocassionally 'flat-line' at 0.00V and then come back to life when the engine revs change up or down. The map on my engine adapts to give a Lambda Fuel Correcton on 4, 5 & 6 of between 30 & 40% (the correction on 1, 2 & 3 is half that at about 15%). I've tried re-setting the maps but the correction returns after a few minutes.

The car has been recently serviced and new plugs gapped @ 30 thou were fitted. There feels like there is a misfire when the car is pulling away in 4th or 5th at lowish speeds (20-30mph) which was something it never used to do. The misfire was there before the service as well.

Apologies for the thread hi-jack Kenny

Below is a screen shot of the diagnostics;

Cheers,
Graeme

[worty]

"Any thoughts on what may need replaced?"
MOT tester !
worty

[jagracer]

jdearden said:

If there that close. I would run it low on petrol and put some injector cleaner in it. Get it hot and retest it. Should then go through.

worty said:

"Any thoughts on what may need replaced?"
MOT tester !
worty

These

[leeshell]

jdearden said:

If there that close. I would run it low on petrol and put some injector cleaner in it. Get it hot and retest it. Should then go through.

I did this too