I have a uk MY98 turbo 2000,it has a power fc ecu with various mods,when the car was mapped by JGM this time last year it was running a complete decat exhaust,i have recently changed the decat downpipe for a second hand Ninja 100 cell high flow downpipe,i took the car to an mot garage this morning just to test the emmisions,and the car failed,before the test,i took it on a nice long drive of about 28 mile,14 of which was driven off boost just to get the car warmed up,and the last 14 was driven mainly on boost on a dual carriageway.

Now the CO2 level was at about 1.00 and so was the Lambda level.
the mot tester has said both values need to be around 0.28 and has sugested that the Lambda sensor may be at fault.I have monitored the Lambda voltage on the power fc commander and it seems ok,pulsing from 0.2v to 0.68v.
Would the fact that the car was mapped for a decat downpipe,and now i have changed to a sports cat have anything to do with this,or is it more likely it is something else.

 

mine should perhaps have failed the last 2 years
......despite weakening the mixture drastically at the 3k point they do the test at

.....fortunately, the garages were ...lenient

 

bump

 

I would personally say yes, it would make a difference, and may need to be mapped again.

But i would definitely advise calling JGM on this matter and having a discussion regards to this.