4 replies to this topic

[cdaspink]

My mini failed its MOT again today on emissions

Its a 94 Mayfair open-loop CAT (it has a carb/NO lambda sensor as standard)

The readings from the print out are as follows... (exactly as it reads)

CO 6.04 %vol
CO2 10.50 %vol
HC 155 ppm Vol Petrol
O2 1.11 %vol
λ 0.87

RPM 0
OIL 10

Can anyone with a better understanding of these figures point to any conclusions as to the likely cause of the failure.
Anything i can do at home to check and remedy the cause without shelling out too much cash!

Cheers in advance

Chris

[The Matt]

Get it tuned!

Basically, I'd say from those readings that the mixture is too high. Was the engine nice and warm when it was tested?

[minidaves]

fuel mixture or choke is sticking on

remember it dont need to pass a cat test

dave

[cdaspink]

Yup, cat was nice and warm and when you say it doesnt have to pass a cat test what exactly do you mean? Does it just have to pass basic emissions as its open loop?

In regard to the tune, can these carbs be tuned to any great extent at home just to get it through the emissions test?

Thanks for the help

Chris

[Silicon Skum]

Yup, cat was nice and warm and when you say it doesnt have to pass a cat test what exactly do you mean? Does it just have to pass basic emissions as its open loop?

Carb cars (even with the cat fitted) DO NOT have to go through the tighter emission "CAT" tests for fuel injected cars (where CATs CAN do something usefull), the only test they need is the standard "non CAT" test for older engines. There is a cut-off point for this, and I belive it's the end of 94 - so your car's still within the cut off point.

Those results of the test show that your engine just needs a tune up, it's running too rich (or they tested with the choke out).
The max emission limits for your engine are:

HC <= 1200ppm
CO <= 3.5%

And thats it! If it passes those two - it's passed the emissions test.

SS