Merc Failed MOT On Emissions - Repairable?

[Whitespirit66]

My brother has a petrol 1998 Mercedes C200. Don't know exactly what aspect of the MOT emissions test that it's failed on yet, but he's already started talking about scrapping it. It doesn't smoke or leave a blue haze, and runs really well. Apart from a few rust spots, the car runs really well and is very reliable.

Is it worth repairing? Are there any common faults with these cars that can cause this problem?

 

[Burnerman]

This has a fairly basic emissions system - at least when compared with today's cars.....it could be a catalytic converter, lambda sensor or air mass meter issue so we need more info.
These cars are well supported with second hand parts if necessary.
John

 

[Avocet]

I agree. Well worth spending a bit of time just finding out exactly what it failed on. Could be something as simple as a small exhaust leak!

You need to find out what the CO and HC were at idle and fast idle, also the lambda reading, then report back.

 

[Whitespirit66]

Thanks for your replies. As I thought, more info and could be any number of things. I don't have much faith in the garage where he goes for repairs, as they are great with nut and bolt things, but a little lacking in the stuff that involves anything computerised. Bit like myself - analogue people in a digital world.

Will get some details.

 

[Avocet]

There should have been a little printout from the gas analyser. If he still has it, that would be useful. Even simple things like a new set of plugs can help if it's borderline.