That time of year again... Failed for the 2nd year Iv'e had it !

[Mark-RS]

But not as substantial as the last time

M.O.T day gives me the following...

Headlight level is low.

Rear pads, which I knew were getting low anyway.

And Emmisions ! Which has suprised me !

Only failed on the Lambda readings, which judging by the paperwork should be between 0.97 and 1.03. Mine reads 1.16

They didn't really have a clue what the issue was but said, maybe exhaust leak, which they didn't find on inspection, air leak or sensor issue ?

[Mark-RS]

So any advice on things I can get the garage to look at for this Lambda reading ?

[simonpoulton]

Check your OE exhaust (if you still have it) around the welds on the resonators. Mine had cracked and was giving high lamda readings. Replaced with Milltek naturally...

[Ajc]

Could also be a cat on it's way out . Did he check the reading on both tips or just the one ?

[Mark-RS]

Only checked on one tip. Passenger side.

Left it running at about 4krpm for about 10 mins which I though a bit much...

[Daveperc]

The hotter the better to get low readings.

[R56WUF]

My previous RS6 failed on the emissions test at Dundee Audi. I went and drove the car for about 1/2 mile with the car in second gear at approximately 60mph, took it straight back and the tester hooked it up and it passed. Always worth giving the system a wee blast.

[Mark-RS]

I did take it for a run before going there, but due to it being -2 I couldn't really give it any stick

I really hope it's not the Cat... Don't see why it would be ? They don't go very often do they ?

I'm hopeful a service and a good check for leaks in the system should cure things

[PipRS6]

Yup, cats don't work unless they're warm. That's the point of the pre-cats. Closer to the engine they warm up quicker. Give it a good thrashing then ask the tested to do emissions first.

[Shoppinit]

What do the car's lambda probes read? If they are not complaining and the car is failing emissions then it seems likely that one or both have failed.

[Ajc]

Lambda reads air fuel mixture , they had a certain amount of tolerance , however I think the car uses a mixture of lambda and egt top work out how it needs too tweek it's running. In the turning world egt a bit more too . On the car the pre and post lambda is checks and altered , though I think the pre is more for the sia side and pre heating the first cat . I service and fresh filters can go a way too changing lambda reading though , so may be worth trying it if you've not already

[Ben_r1]

Doesn’t a failing cat usually give an eggy smell? But yes let’s hope it isn’t that, I’m betting it’s another ‘engine out job’.

A friendlier mot tester could be the easiest solution here

[Ajc]

It is possible too get the cats out without dropping the engine , but it does still involve dropping the back end of the sub frame down and a really long extension bar .
Mine is soon too have no cats at all , so I wont have to worry . I work at a place that does mot's now

[Ben_r1]

It is possible too get the cats out without dropping the engine , but it does still involve dropping the back end of the sub frame down and a really long extension bar .
Mine is soon too have no cats at all , so I wont have to worry . I work at a place that does mot's now

I was quoted for an engine out job to fit a pair of decats on mine as the specialist was adamant it’s near impossible to remove the bolts without the studs snapping.

[Mark-RS]

Oil change and Plug change and the readings are now within normal levels.

Back in tomorrow for the retest.