Hello

Hopefully somebody can shed some light on an issue currently stumping myself and the garage

Car is a 2006 VRS tdi (pre fl).

When I bought the car, the turbo needed replacing. I took it to the garage for a dpf removal, remap and replacement turbo. It turned out that the car had been previous mapped by customcars (full boost, hence dead turbo) and the dpf had already been cleared out so a garret turbo was put in, a more sensible map and off I went.

The car was a little overfuelling but the mpg never changed and it passed its mot. Aside from having a lot of prodding, nothing else was done.

Today, the car went in for its mot and failed miserably on emissions to the point that hooking it up to the test machine in idle causes it to go off the charts. There is never a huge amount of black smoke no matter how hard I drive it, the performance has never changed as far as we can tell (both of us liken it to a train pulling) and the overall tank still gets roughly the same amount of miles (about 480-515 depending how hard I drive it).

I commute 30 miles each way every day to work, there doesn't appear to be any extra rattles or bangs and everything seems the same as day one. The garage also changed the map and that made no difference. It was mentioned engine wear would cause this issue but that would normally hamper the performance.

Sorry it is such a long post but I wanted to get the whole story across but does anybody have any ideas as to what it could be? Many thanks

The only emissions test performed on a diesel is a metered smoke test or soot test.

 

"During this test, a calibrated smoke meter is used to assess the density of the smoke from compression ignition (diesel) engined vehicles.
The engine will be accelerated up to governed speed and the smoke density measured.
Engines that emit very little smoke and achieve a meter reading of 1.5m-1 or less will pass the test after the first acceleration. 
However, if the test is not passed on the first acceleration a further two accelerations will be carried out.
The average of the three acceleration readings will be calculated and if the reading is at or below 2.5m-1 for non-turbocharged engines or 3.0m-1 for turbocharged engines, the vehicle will pass this element of the test.
However, if the average is higher, a further acceleration will be carried out, and the average of the last three readings will be calculated. 
This will continue up to a maximum of six accelerations. 
If the average of the fourth, fifth and sixth accelerations is higher than the appropriate level, the vehicle will not pass the test."

 

Did the MOT station follow the above procedure?

 

Also, you should have the fail certificate, what were the actual measurements provided by the MOT station?

 

To tell you it was simply 'off the scale' isn't good enough, they should be able to provide you with the actual numbers.

Edited 11 November, 20169 yr by silver1011