My Scoob had its first MOT today and failed on the fast idle emissions test. It is a MY99 Turbo and the only modifications are a Magnex bacbbox, Magnex centre section and a panel filter. Since it still has a catalyst in the downpipe I was under the impression that it should pass. The fast idle emissions were as follows:

CO 2.43 max of 0.3 required to pass
Lambda 0.937 pass is 0.97-1.03

On Power Engineering's rolling road last November the CO was <0.1. Given that it is failing on the lambda readings, which I assume would be unaffected by the removal of the rear catalyst, I am wondering if something else is wrong.

The MOT tester thought the engine didn't sound right, although he wasn't familiar with Scoobs, and commented that it didn't pick up well when he was manoeuvring it. He may have a point since when I was driving yesterday it hesitated a couple of times on light throttle around 2500-3000 rpm, although it may have been my imagination. Also when I accelerated up a slip M-way road it wouldn't gain at all on a Honda Accord Type-R, which is about a second slower from 30-70 mph.

Could someone give me some advice on whether or not anything is wrong with my Scoob or if I should have it retested with the rear cat back on.

Alan

Bribe the guy. Give him 50 and he will use someone's micra for the emission's records. Did it, it works! :D

What were the HC reading? if they are high possible misfire if not get your lamda sensor tested. HC pass limit is 200 if its got a misfire it will be up above 1000(at least) hope this helps.
Rob

Sounds like it could be as simple as the filter or plugs. Have you changed them recently?

In response to above queries

I assume the HC was OK otherwise the tester would of said something.

The air filter was changed about 7000 miles ago and the it had a 30,000 mile service 5000 miles ago, at which I think the plugs are normally changed.

Alan