NCT emissions failed, any ideas what is next?

shamu2new

05 Passat Petrol 1.6 failed NCT

Emissions
Eng Temp 81%
Low Idle 860rpm - CO 0.12 Vol% HC 33ppm - ok
Lambda 1.00

But
High Idle 3270 rpm - CO 0.25vol% HC 26ppm

was given a good Italien Tune up before going in - any ideas what I should do next is it a petrol cleaner job or into a garage - I only need it down by 0.5

Looked at last years and it passed at 0.20 so somethings not right with car - oxygen sensors done. Nct guy said it might be a temperature sensor as the gauge is staying just down below 90

What do yous think?

Thanks

jimgoose

I'd be inclined to get a fault-code reader on it.

BohsCeltic

I thought it had to be above 30% for a fail ?

shamu2new

@jimgoose its showing a catalytic converter issue but it could be any one of a number of sensors apparently.

@bohsceltic - no I checked last years cert and it was .20 for pass then aswell.

I think I will go get some Bardhals put it through it and see if I can get it to pass - at least that will give me time to think.Might try raising some cash and trading it into a garage as wouldnt be happy selling it outside trade if theres a fault - she is 11 years old now.

Am I better to put the Bardahls in or Dipthene and should the tank be clear of them for the retest? would appreciate any help

BohsCeltic

shamu2new wrote: »

@bohsceltic - no I checked last years cert and it was .20 for pass then aswell.

I think I will go get some Bardhals put it through it and see if I can get it to pass - at least that will give me time to think.Might try raising some cash and trading it into a garage as wouldnt be happy selling it outside trade if theres a fault - she is 11 years old now.

Am I better to put the Bardahls in or Dipthene and should the tank be clear of them for the retest? would appreciate any help

I had my test during the week and the sheet says above 0.30% is a fail.
My reading was 0.13% and I didn't add any additives and car is 16 years old.
Any time I used dipetane in the past I put it in before filling up at the pump about 5 days before the test.

shamu2new

@bohsceltic - mind me asking is it a petrol - mabye its different limits for different cars - I dont know?? anyone??

shamu2new

Anyone able to recommend a good VW mechanic in North Co Dublin that could check this out for me? Would need someone who has equipment for emissions testing. Thanks

BohsCeltic

shamu2new wrote: »

@bohsceltic - mind me asking is it a petrol - mabye its different limits for different cars - I dont know?? anyone??

Ye mine is Petrol, it could be different depending on age right enough

jimgoose

shamu2new wrote: »

@jimgoose its showing a catalytic converter issue but it could be any one of a number of sensors...

What is the exact fault code, and what are the exact emissions test results - CO, HC and Lambda?

John T Carroll

shamu2new wrote: »

05 Passat Petrol 1.6 failed NCT

Emissions
Eng Temp 81%
Low Idle 860rpm - CO 0.12 Vol% HC 33ppm - ok
Lambda 1.00

But
High Idle 3270 rpm - CO 0.25vol% HC 26ppm

was given a good Italien Tune up before going in - any ideas what I should do next is it a petrol cleaner job or into a garage - I only need it down by 0.5

Looked at last years and it passed at 0.20 so somethings not right with car - oxygen sensors done. Nct guy said it might be a temperature sensor as the gauge is staying just down below 90

What do yous think?

Thanks

I always clean the throttle body and put in a new set of plugs the day before the test in a now heading for 17 year old 1.4 Bora from new with almost 185K miles up, it failed for the first time ever last year on on high lambda but that was because of a hole in the original back box, now renewed. I also do the same on a 05 Polo but this has only something like 78K Kms up, (high idle CO limit 0.2%)
You are within kicking distance at a high idling CO of 0.25% (limit 0.2%) prior to 04 or 05 the limit was 0.3%)
A few things: that eng temp you quote at 81 ic actually the oil temp and while 81C is reasonably high, I get mine up to over 90C just before the test which might make that vital difference for you. The other item is your temp gauge reading slightly below 90C, on all VWs for years now, when the temp gauge just reaches 90C,the actual coolant temp is only 73C/75C temp and the temp gauge will (should) stay rock steady at 90C until or if the actual coolant temp exceeds something like 105C. Now its unlikely that you have an oil temp of over 80C with a coolanr temp of 75C but its possible, its very easy to see if the thermosatat is passing, just feel the top hose just before it enters the rad, it should be almost stone cold until your temp gauge passes an indicated 85C or so, you could possibly have a coolant temp sensor fault and this can have a big effect on emission levels. If you knew someone with VCDS it would be worth getting a diagnostic on it. However throwing a tin of fuel additive into it might get you over the line without spending too much money but if there is one thing that I may re-emphasise is make sure that you have a new set of plugs insalled, you dont need those super duper ones at €80 or so, a €20 set of the copper cored ones will do the job fine and you can always change them back after the test if you feel like it. Good luck.