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View Full Version : Audi quattro 2.8 coupe de-cat MOT emissions



woodsyv12
18-12-2007, 11:05 PM
Hi Guys, can anybody help?, I have bought a 1995 2.8 coupe quattro which has been de-catted but now it's MOT time and the emissions are just a bit too high. Has anybody else had this problem and how can I get round it i.e. is there away of adjusting the fueling or can I trick one of the sensors to make the engine run leaner. I have already put in a new set of plugs and ran the car on BP ultimate for a few miles, this reduced it from 0.6 to 0.5 but I need 0.3. I tried opening a air pipe into the inlet manifold but the lamda sensors adjusted the mixture to suit. Thanks.

Crasher
18-12-2007, 11:16 PM
You won't trick it, the gas analyser can tell the lambda isn't at 1 and the HC will be too high if it is too lean, the test isn't just Co.

woodsyv12
18-12-2007, 11:57 PM
A couple of idears have sprung to mind. I could advance the ignition a couple of degrees by moving the crank sensor as that should help with combustion or maybe bridging the lambda sensor plugs with a resistor to increase return voltage to the ECU thus fooling it into thinking the mixture is too rich
How about a new pair of lamda sensors??? the ones on the car are originals and have done 100K??
It's just idears going round my head at the mo.

RickT
19-12-2007, 12:55 AM
You wont trick it... also its on record if it should have a cat fitted... so when they check under the car and see no cat its failed anyway...

just refit it.. it only take an hour max..

Rick

Crasher
19-12-2007, 02:22 PM
How about not breaking the law and adding to our already over polluted atmosphere and refitting the catalyst!