1.9dg failed C02 Emissions test MOT

[garry247]

Had my engine reconditioned last year but just failed the MOT emissions test?

There is a crack in both down pipes from the back part of exhaust system. The MOT guy says that could be it or the petrol tank?

Any ideas?

just looked at a new exhaust and its quite expensive, especiually as i want to do a respray this year?

cheers,

Garry

[marlinowner]

When my DG failed on emissions the MOT tester suggested changing the oil, I did and it passed. Or take van for a good run to get the oil hot and purge any petrol that's got in it. Might be worth checking the air filter, or leave it off for the MOT to weaken the mixture a bit.

[garry247]

Im going to put some redex in, take the oil filter out and take it back for a retest

hope that works

I cant see the exhaust making the co2 worse as if anything it should make it better.

the acceleration jas been a bit lumpywhen my foot goes past half way down so there may be something i the bottom of the tank that got through to the jet in the carb. Who knows.

could that cause high co2

Have no idea what causes it?

[itchyfeet]

Afaik co (not co2) is only measured at idle
so there is an idle mixture adjustment screw on the pierburg 2e3 which may do the trick
ideally you need a co meter before messing with it and to know it's right.
you could ask your mot tester to tweak it for you

clockwise lowers co

[Aidan]

what exactly were the readings that it failed on ?
CO maybe right but HC high which is usually the vacuum pipe for the brake servo having gone porous and allowing the left bank to run lean, you adjust the co to get co in spec but HC go over limit as right bank is running rich

[garry247]

Thanks guys,

Ive been in IKEA lock down last few days as my daughters new bedroom has been filled with IKEA boxes by my wife. I have just finished.

Thankyou for your poins above that was extreamly helpful. I wil tell the MOT guy about the screw and the pipe.

Fingers crossed.

Garry