Emissions - MOT Fail help needed

[jamiehol 0]

I've had my VR Raddo in for its MOT and its failed on a couple of things, one flexi brake pipe which is a nice easy fix, but more worringly I have the following fail.

 

"Exhaust emissions carbon monoxide content after 2nd fast idle excessive"

 

Annoyingly I don't have the emissions print out to see exactly what was what but then I haven't been charged for the failed MOT so I can't compain too much.

 

I will do some google research as well but does anyone have any Raddo specific causes for this fail.

 

Thanks,

Jamie.

[jamiehol 0]

Well I have just had a quick look at the car.

 

Couple of things that stand out, there is a slight blow at the rear of the cuit case silencer I could see that if the air leak was before the cat or lambda it could affect the emissions but after it surely it shouldn't have a massive impact.

 

Also on a quick scan with VAG COm I had a couple of faults for the injectors and one for the immobiliser but there was also one mroe importantly for the 02 sensor being open circuit, I cleared the fault and tried the measureing blocks and the lambda satyed at 1 but the fault code hasn't come back.

 

So I guess my next port fo call has to be testing the sensor ? or does it sound like I am barking up the wrong tree.

[MADFISH 0]

It wouldn't hurt to change it anyway, if it's been on the car for sometime, emmissions are always troublesome, does she use over average fuel ??? Sometimes the cat can get knackered if she's running rich but if you're lucky it's not been damaged beyond repair after you rectify the problem, it may need a new cat though but sensor is the cheaper try first :) Check the other sensors, water temp can be troublesome and pretty cheap to replace but I think you're going in the right direction !!!

[jamiehol 0]

As far as I know it is the orginal lambda sensor from 1996 so I think it is worth swapping it out, its difficult to gauge fuel consumption as the car has been off the road since the new year it certianley smelt rich if you know what i mean when started from cold.

 

Looking at the temp being reported in Vag Com to that reported by the dash gauge they both seem about the same so I think that is ok. I think a mate has a spare cat of a VR that I could try if it is needed.

 

Will rpeort back how I get on over the weekend.

[Rocket Ron 1]

I had some trouble before with emissions and it was caused by fitting an induction air filter. Once I returned it to the normal panel type and box it passed.

[jamiehol 0]

I will bear that in mind, the car came with a generic cone filter, and that was fitted for the last MOT when I didn't have an issue with emissions. My track car has the standrad air box so I can always nick that for a test.

[jamiehol 0]

Just to cloe this off, due to ECP and GSF not getting the new sensor in for Saturday and with work getting in the way I didn't get chance to replace it before the MOT retest today.

 

However good news the MOT passed, my tester wasn't quite so busy today so had a quick look and noticed a tiny leak between the exhaust manifold and downpipe a bit of exhaust paste and it passed. I had noticed a hissing near the throttle body but it sounded like it was coming from the ISV, but it was obviously the manifold to down piep joint.

 

Will get some new gaskets when I get chance to affect a proper repair.

 

Thanks for all the suggestions