Failed MOT on Emissions

[Rob G]

Afternoon!

My Clio failed MOT today on emissions (amongst a few other small bits).

Spec is:
2004 172 Cup 105K miles
Standard Exhuast (although non OEM replacement)
Standard CAT
Recently replaced 2 x Lambda
Cup racer style Induction kit with Ph1 airbox (relocated battery to boot)

Results are below (failed on CO level):


What would be the best course of action to bring it within the MOT requirements. I have added a bottle of Petrol system cleaner to the tank already.

 

[Gus]

You could chance it and give the car a really good warm up before getting it re tested.

Replace spark plugs. clean the lamda sensors depending on how new they are. Coil pack possibly.

 

[StuOwen86]

put the probe in the car next to yours job done lol saved loads of hassle haha

 

[Rob G]

Haha if only you could still get away with that!
I'm going to change the plugs then see if I can get it nice and warm before testing.
Stupid question but what causes a high CO reading?

 

[smith647]

Cars that run rich read High CO readings... Unburnt fuel in exhaust gases is probably causing it.

 

[Don]

My 182 'fails' the CO2 test every year, but the tester knows its a good car and he will take it out for a blast and bring it back and test again and it passes.

 

[nd-photo.nl]

CAT might be shot? How old is it?

 

[Rob G]

As far a I knoweth cat is original. Don't think it's that though as it passed everything but CO

 

[Blerg]

The hydrocarbons are getting higher between fast idle 1 and 2 which is normally indication of unburnt fuel and would say very normal if a touch high but not to worry about. And the Co goes sky high which is normally the indication of a knackered cat or worst case burnt oil in the emissions, for example rings or valves stems but you'd see this for that to happen.

My bet is it needs a cat, I'm sure you don't have worn engine internals and if the engine was running incorrectly such qs poor timing, missfire etc there would be an eml. Though if you opt for a pattern/aftermarket/race cat it will need to get very got hot to get within the limit of 0.20 and don't tend to last around 10 years which a genuine oem cat does.
Those additives are more or less a load of crap, that 15 min drive it tells you to do after pouring it in does all the work.... Getting the cat to temp and the ecu controlling fuel etc at its optimum rate.

 

[Blerg]

Just for a general reference.
CO fail normally means cat aging or failed/burning oil/other engine issue
HC fail normally means unburnt fuel which can lead to premature cat failure and is normally pickup via the ecu unless it's been mapped
Lambda fail normally indicates an exhaust leak or other engine issue

Those are just a general reference and the first things I would test or consider depending on what emissions wise it failed.

 

[Dan@SJM]

Another generalisation is that a fail of 0.7 co and above usually indicates a failed lambda

Below 0.7 but still a fail is usually cat.

 

[Rob G]

Well it failed again, on pretty much the same readings!
New cat it is!

 

[Budgie]

Find a sensible tester before you do that.

 

[Blerg]

If the tester has done all he can to ensure the engine and cat are as warm as possible he can't 'make' a car fail on emissions so won't matter what tester you get.
I guarantee a new cat will sort that

 

[Rob G]

Yea I took it for a proper run before hand, and the tester was running it for 30 mins odd trying to get some heat in the cat!

 

[Blerg]

Ah so he's done all he can without changing parts! If the levels are still roughly the same get yourself a cat on there, report back.

 

[Rob G]

Changed the cat today.
No wonder it failed, someone had completely gutted the old one!

 

[Turbo steve]

Explains it all

 

[Mr Plums]

As it passed then?

 

[Goodj]

Changed the cat today.
No wonder it failed, someone had completely gutted the old one!

Sik mod dat bro.

 

[Blerg]

Good work! Why anyone would do that makes no sense. Just buy a decat and swap on mot days

 

[Rob G]

Managed to get it booked in for re-test this morning! All passed and good to go.
Hate to think how much it would have cost if I wasn't able to do the work myself (the parts needed came to £300 alone (needed a new rear calliper and a few other bits also!).

 

[Goodj]

If only you'd get a spare VW Badge kicking about, you could have avoided all that buggering about

 

[fixedgear]

Changed the cat today.
No wonder it failed, someone had completely gutted the old one!

Not me! I think the last MOT was a bit suspect after the bits I ended up fixing in the time I had the car.

Glad you're sorted now Rob.

 

[Rob G]

Haha yea it did seem that way! All is good now though!