Jezzaglg

This model.
Hi my 2008 c200 coupe kompressor failed its mot on all 3 emissions tests.
took it to a local independent German car specialist who has repaired leaky rubber hoses under the supercharger, replaced 2 lambda sensors, replaced the catalytic converter (2 of in the exhaust), ran a fuel treatment through it and it is still failing th CO test reading 0.5/0.6. The pass figure is 0.3.
They said they have reset the ecu, still no luck.
The garage have offered to keep "researching" but when I asked what exactly they weren't sure.
they said the compressions were fine as was the air filter.
I am reluctant to keep going at this point.
does anyone have any suggestions on any potential issues that could cause this.
of note it has a multi point lpg system on it which has been switched off throughout all of this, when switched on it flies through the emissions tests.
update from the garage they believe it is a fuelling issue and is running rich for some reason, but offer no possible solution for it.
the garage also swapped the air mass meter and whole air box from another vehicle they had in, this made no difference.
HELP please.
regards
Jez

chassis

Welcome! Please post a photo of the C200. There is a section of this forum for your vehicle, where if you post the question there, owners will be able to help.

Jezzaglg

Picture of my mod my merc added FYI.
Car popped into kiwi fit for attempted diagnostic, they couldn't do any testing as they aren't allowed to work on lpg cars (apparently ) but their master technician said he thought it was sucking air in somewhere pre ignition causing it to run rich.
regards
jez

chassis

Looks great!

dbldpr

Welcome nice looking ride