My 1991 de-catted S2 had its MOT today.
passed the emissions test fine (as it should - it's only cars registered since 1992 that are subject to a more stringent emmissions thresholds in the test with the only technical way to get through them being a functioning Cat), but failed on dodgy indicators - water in the rear light clusters. Argh!
The rotten egg smell is common with cars with Cats when they're running from cold. It's to do with high sulphur levels in European petrol, incomplete combustion due to cold-running, a not fully-warmed up Cat not catalysing effeciently, resulting in the Cat producing Hydrogen Suphide (the egg smell).
I think the only way to get round it is to try using different petrol, and maybe if it still persists, ditch the Cats completely, or get new ones that will be more efficient.
Also, in theory, a Cat can actually INCREASE the levels of CO2 produced as it catalyses reactions various emmissions to CO2 and water.
It's the 1992 threshold that's significant I believe.
passed the emissions test fine (as it should - it's only cars registered since 1992 that are subject to a more stringent emmissions thresholds in the test with the only technical way to get through them being a functioning Cat), but failed on dodgy indicators - water in the rear light clusters. Argh!
The rotten egg smell is common with cars with Cats when they're running from cold. It's to do with high sulphur levels in European petrol, incomplete combustion due to cold-running, a not fully-warmed up Cat not catalysing effeciently, resulting in the Cat producing Hydrogen Suphide (the egg smell).
I think the only way to get round it is to try using different petrol, and maybe if it still persists, ditch the Cats completely, or get new ones that will be more efficient.
Also, in theory, a Cat can actually INCREASE the levels of CO2 produced as it catalyses reactions various emmissions to CO2 and water.
It's the 1992 threshold that's significant I believe.

and now just the brakes, alloys, turbo to sort plus working out a way to get the wheel liner bolts holding the bumper on undone so i can get the belts and oil pressure sender changed then i am there.....
Hopefully yours will be on song again soon Tom, have mine out on the track next spring too
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