My MK4 GT TDI failed it's emissions today. 185K miles.
I asked the tester on the type of failure and he wouldn't say, other than 'it was beyond manufacturer limits, and it the exhaust smelled really bad when he stood behind the car'.
I have to agree on the smell. It can be absolutely acrid on startup, but it's been like this for years and passed before. It's a similar smell to burning car tyres. No joke. Lingers for ages if the smell gets on your clothes. Gets slightly better after the engine has warmed up (10-20 miles). Others have reported this issue with high mileage VW TDIs. The car is still returning 50+ mpg, so the fueling can't be that much out.
So I asked for the emissions print out and it can be found below.
I don't understand what it's saying about emissions other than it's failed. Don't they monitor different gasses and particulates? These are normally listed. This will give me an idea of where to start fault finding.
I gave the car an short high RPM run the day before the test, to clear the soot from the exhaust and turbo. This normally does the trick, but not this time.
The car has been sat for about 9 months on a battery maintenance charger to stop it sulphating.
The next step is to run half a tank of fuel cleaner through the engine, and hand it over when the engine is hot (it wasn't during the test - just warm).
It would be nice to understand the emissions report though.