2009 Mini Cooper S Clubman Miserably Failed Emissions Test

[stevemcs]

It could be the Cat

[apsona]

Ok the cleaning was done and it's running like new with no hesitation anymore. The big test will be the emissions test when it goes for it's test as last time it was bad, bad, bad.

We ran it through a better OBD scanner and it detected that codes had been cleared! We retrieved the code which was a misfire in cylinder 4.
It's too early to say if all is ok now but I am interested to know what might cause a misfire in one cylinder apart from the coil and spark plug of course ....

[tryagain]

I have had three minis since 2011 ,two have suffered from hesitation at acceleration. The first was misfire cylinder 4 on my code reader. That was cured with four new spark plugs and one coil pack for just one cylinder. That car was a 1600 cooper. second car no codes and cleaning the vanus solininoid and set of plugs cured . That car had 26000 miles on clock. I posted earlier in error that I changed vanos solenoid , I cleaned it. They advance the camshaft and supply extra oil to cam under load. The oil was changed every 6000 and still a load of muck on it.I have a three cylinder 1500 now on a 15 plate it has only done 1300
I really am impressed with the performance from this engine. You don't mention changing the leads, could be one of those

[tryagain]

Should read 13000

[apsona]

Quick update .. misfire in cylinder 4 code has gone away. I am trying for the emissions test again tomorrow for the french MOT so fingers crossed. I have no idea if it works but i put some cataclean in this week just for the hell of it.

The car does go all jumpy/jerky when driving in gear at 1000-2000 rpm after which it behaves well.

Fingers crossed for tomorrow and I'll post any update

[apsona]

All sorted, passed the emissions test easily this time. In summary this is what i did to the car and I don't know which one or combination sorted the issue:

- walnut blasting
- Changed oil, oil filter, air filter, spark plugs, all ignition coils, fuel filter
- Bottle of Cataclean into 14 litres of petrol, ran to empty, filled up and the morning of the test i took it on a fast blast along the motorway and back for around 60 miles.
- Drove straight to the test centre, arrived 5 mins before my appointment
- Car straight into the emission test
- Passed :-)
- Car runs well now

I hope that helps others. Cheers,
Paul

[df76]

Appreciate the update, glad it’s sorted. My mini has felt a little “lumpy” on initial start up recently, but a couple of tanks of Vpower seems to have solved that for the moment. The minis are clearly fuel sensitive.

[paultownsend]

Assume this is a N14? If you are planning to keep it, is it worth considering a catch can set up to reduce to carbon re-build up? We have a N18 which I beleive has a revised setup.
Also fuel. Do you use VPower etc which is said to have cleaners in it? We are lucky as we have one nearby, but we use Costco fuel. They advertise heavily their fuel with cleaning additives. They do a VPower version. But even the standard seems better than supermarket fuel. Runs smoother, gets more miles per tank and you get more pops from the exhaust on overrun. Is it running cleaner? Beleive morrisons took out the additives from their fuel a while ago.

[apsona]

Indeed it is an n14 ... good point about the catch can. Thx

[paultownsend]

I need to look into it for our N18.

[stevemcs]

N18 doesn't suffer as bad as the N14