So when you drive a car with 4 exhausts surely the emissions out of the exhaust number 1 say is less? How do they compensate ??

Isn't it measured in PPM?

eh?
(@ james)

Say emissions = 12

If you had 4 exhausts for the emissions to flow through, then the average emissions flowing through is equal to 3..

So the more exhausts you have then the easier it is to pass the test??

PPM=Particulates Per Million (or summat)

So it doesn't matter how many exhaust tailpipes are at the back of your car, the gas coming from each of them will be just as dirty whichever you put the probe in*




*Simplification.

>sigh<
they measure the %of co2 and other stuff in the exhaust, the proportion is the same for each exhaust if all things are equal. There my be 1/4 of the volume but the ratio of the gases will be the same so the machine will just have to sniff for longer to get a sample

you thinking of having church organ style tail pipes to get round the test? - just fit a 1960 vin plate and bypass the whole thing

Im not an not tester so I've no idea how it works which is why I asked

But that makes sense

Ok, so it failed but only on emissions (again). I checked the tappets which were fine,plugs are new and gapped right, timing is spot on with the strobe engine breather is a proper one and about 6 months and 40 miles old. I took me screwdriver and matey let me dick about with it prior to the test, nothing I did could get it below 6%.

Running a bit rich. Clogged air filter? Float level too high?