171 Skoda, 52000km - NCT emissions fail

LeoD

Hi there, took car for its first NCT at the weekend and was surprised when informed that it failed on emissions. It's a 1L petrol Octavia and there's never been an issue with it - it was also serviced by a main dealer last week. Since last March, it has hardly done 500km due to working from home. (and most of that was done a trip to Dublin in June - it's done about 20-30km since)

Low Idle:
CO 0.01 vol%
HC 0 ppm

High Idle:
Lambda 1.05 (range 0.97-1.03)
CO 0.11 vol%
HC 0 ppm

Called dealer - was advised to drive it for an hour before test which seems daft. Test is at 7:20AM also so won't be doing that. Do we think the lack of use could be an issue? Should I drive it as much as possible between now and the retest? Any other probable causes/fixes? Thanks...

FGR

The lack of use hasn't helped especially if any driving done has been short and not allowed the engine to heat up fully.

I've always been told to give a car a good run before bringing it for a test. Fortunately my nearest centre is in the next town 20 minutes away so I can give it a good going on the way there. Once you give it a good run at 100km/h you should be ok going on.

There shouldn't be any other problem with your car.

bazz26

Could be a combination to be honest. Certainly not been driven in nearly 10 months hasn't helped and getting it tested while the car wasn't fully warmed up after such little use in 10 months probably compounded it.

LeoD

FGR wrote: »

The lack of use hasn't helped especially if any driving done has been short and not allowed the engine to heat up fully.

I've always been told to give a car a good run before bringing it for a test. Fortunately my nearest centre is in the next town 20 minutes away so I can give it a good going on the way there. Once you give it a good run at 100km/h you should be ok going on.

There shouldn't be any other problem with your car.

I may have driven it twice since June - once was recently to give it a wash as was getting covered in green mould! The NCT centre is 10km away. With the 5km limit at the moment I might just have to go up and down the nearby motorway a few times each day...

i57dwun4yb1pt8

the usual is to bang in some Dipethane into the tank an drive her hard for a while .
and especially the day of the test , warm it up good .

though i have had errors like that in NCT and specialst garage checked the car and it was fine , there was rumours of the probe not being put in deep enough by nct chap ( giggidy) by the garage who tested it .

re test and it was fine and i did feck all to the car to fix it - you can take that as you will.

it was an 02 audi a3 and this was 2013 when it was tested.

LeoD

The carbon monoxide and hydrocarbon levels are well below the thresholds - it's the oxygen/fuel mixture ratio that's the problem. I don't know what Dipethane would do to change that?

i57dwun4yb1pt8

might clear dirty fuel supply / injectors if thats causing fuel mix issues.

im out of my depth now ...

jmreire

LeoD wrote: »

I may have driven it twice since June - once was recently to give it a wash as was getting covered in green mould! The NCT centre is 10km away. With the 5km limit at the moment I might just have to go up and down the nearby motorway a few times each day...

I think that taking the car over the 5 klm limit would be allowable as being an essential trip. Then 5th gear all the way to the test centre on the day of the test, and she will be well warmed up by then, and even a few 5th gear trips in the days before the test will go a long way towards making up for the lost driving time.

Newuser2

jmreire wrote: »

5th gear all the way to the test centre on the day of the test, and she will be well warmed up by then, and even a few 5th gear trips in the days before the test will go a long way towards making up for the lost driving time.

3rd or 4th gear no?

Del2005

Marlon Mammoth Tomato wrote: »

might clear dirty fuel supply / injectors if thats causing fuel mix issues.

im out of my depth now ...

Petrol sitting in the tank for 10 months won't have helped.


Brim the tank and take it for a good blast up and down the motorway the night before the test. Drive it to the test in 3rd to get it good and hot..

jmreire

Newuser2 wrote: »

3rd or 4th gear no?

4th for awhile, but no lower. The whole idea is to keep the engine revs up above 2'000. Say between 2'200 and 2'500 RPM. So does not really matter which gear you are in. About 18 Mth's after we bought a new 1.6 Superb 1.6 TDI, the engine management light came on, and I had to take it back to the main dealership in Limerick, about 25 miles away. As it had only about 15'000 Klms done, and mostly short drives, I thought it might be DPF problem, so I drove it the whole way, driving between 4th and 5th gear all the way, but keeping the RPM at 2'500 ( and even a bit more at times !!!:rolleyes: ) The actual problem was a faulty sensor.

btree

OP, can you check the below link, please. It seems similar to your issue with an exhaust leak, and Oxygen can enter the exhaust pipe.

https://www.boards.ie/vbulletin/showthread.php?t=2056162148&page=2


Can you slightly hammer a potato on the hole of the exhaust tail and turn on the engine? If the car can force the potato out, then there would be no leak. I tried to check and it worked.:P

My car failed NCT for high CO before Christmas and I bought almost a full tank of premium petrol at Circle K. Drove the car at third gear for 20 minutes at about 80km/h just before re-NCT. I kept the car running when I was waiting outside the test centre. All passed.

LeoD wrote: »

Hi there, took car for its first NCT at the weekend and was surprised when informed that it failed on emissions. It's a 1L petrol Octavia and there's never been an issue with it - it was also serviced by a main dealer last week. Since last March, it has hardly done 500km due to working from home. (and most of that was done a trip to Dublin in June - it's done about 20-30km since)

Low Idle:
CO 0.01 vol%
HC 0 ppm

High Idle:
Lambda 1.05 (range 0.97-1.03)
CO 0.11 vol%
HC 0 ppm

Called dealer - was advised to drive it for an hour before test which seems daft. Test is at 7:20AM also so won't be doing that. Do we think the lack of use could be an issue? Should I drive it as much as possible between now and the retest? Any other probable causes/fixes? Thanks...

Atlantic Dawn

Also if you were sitting in the car before the NCT with engine idling that won't help either.

LeoD

btree wrote: »

Can you slightly hammer a potato on the hole of the exhaust tail and turn on the engine? If the car can force the potato out, then there would be no leak. I tried to check and it worked.:P

If I fail a second time I might try that...

Stallingrad

btree wrote: »

Can you slightly hammer a potato on the hole of the exhaust tail and turn on the engine? :P

Make sure you use the right type potato, some can cause Kerr Pinking.

BOSTIK

The car is running lean, additives won’t solve that. There’s clearly no issue with the CAT

The O2 sensor probably needs attention, it might need a clean.
If the car just got serviced last week I’d imagine that the air filter should be OK.

XsApollo

Check for a hole in the exhaust somewhere.
Get it on a lift and go under with engine running.
Tire place might be handier to do that than a mechanic.

Casati

Any car that hasn't been driven like that needs an Italian tune-up. Driving in 5th gear at 2000 revs on the motorway isn't want you want to do - instead take her for a couple of drives between now and the test and when its warmed up absolutely trash the engine up to 6500 rev's in 2nd and 3rd gear a good few times. Dipetine/ Redex might be no harm too as the petrol in the tank is probably very old so as another poster said brim it with new petrol too before you do the tune up.

Dilbert75

Leak after the cat would be my guess. Had a similar result on an old car recently and a weld on the joint between the rear box and the pipe sorted it.

LeoD

Car retested and passed this morning - lambda reading at 1.01. Didn't do anything to car - just filled the tank (was almost empty the last time) and drove up and down the motorway between two exits a few times.

jmreire

That's good advice...drive as much as possible between now and the test, and make sure that you give it a good long drive the day of the test, and fill up with fresh fuel. Petrol deteriorates overtime . Time it so that you won't be waiting too long.

LeoD

jmreire wrote: »

Petrol deteriorates overtime.

That's an interesting one. I record when I get fuel as I have a fuel card and the last time I put petrol in the car was September.

Larbre34

I don't know why anyone would think its daft to run an engine for a good spell before a test. Obviously they are built to run at their most optimal when up to temp.

jmreire

LeoD wrote: »

That's an interesting one. I record when I get fuel as I have a fuel card and the last time I put petrol in the car was September.

Its a strange situation all right,, on the one hand, the SIL is saving €100 per week, while working from home.....but is now risking DPF issues, can not being driven enough. When I park up the rideon mower for the winter ( 4 stroke petrol engine ) I use an additive supplied by the people I bought the mower from to keep the petrol "alive", so the fuel does not deteriorate. And for any 2 stroke engines I have ( chainsaw, Strimmer's etc) after each season, I drain the tanks, and then run the engine until it stops due to lack of fuel because the 2T oil forms a gel which clogs the lines, so its essential to clear them before putting them away for a long period. So it's something to remember, and also if you go into most filling stations, they sell an STP additive for petrol or diesel. I use it regularly.. sometimes it can be bought in either Aldi or Lidl for about €6 for 2 bottles. Well worth the money.

LeoD

jmreire wrote: »

Its a strange situation all right,, on the one hand, the SIL is saving €100 per week, while working from home.....but is now risking DPF issues, can not being driven enough. When I park up the rideon mower for the winter ( 4 stroke petrol engine ) I use an additive supplied by the people I bought the mower from to keep the petrol "alive", so the fuel does not deteriorate. And for any 2 stroke engines I have ( chainsaw, Strimmer's etc) after each season, I drain the tanks, and then run the engine until it stops due to lack of fuel because the 2T oil forms a gel which clogs the lines, so its essential to clear them before putting them away for a long period. So it's something to remember, and also if you go into most filling stations, they sell an STP additive for petrol or diesel. I use it regularly.. sometimes it can be bought in either Aldi or Lidl for about €6 for 2 bottles. Well worth the money.

Ah bollix - that's my strimmer f**ked now too. Think I'll be selling the Skoda this year and potentially getting an ebike as a replacement. No need for 2 cars doing a combined 10k a year.

Eric Cartman

Stallingrad wrote: »

Make sure you use the right type potato, some can cause Kerr Pinking.

she's chip-ed laaaad.

jmreire

LeoD wrote: »

Ah bollix - that's my strimmer f**ked now too. Think I'll be selling the Skoda this year and potentially getting an ebike as a replacement. No need for 2 cars doing a combined 10k a year.

The strimmer will be fine, once the fuel pipes are either replaced, and the carburettor cleaned... and there are cases too where they start after a few pulls, and work away. I learned the hard way with a new strimmers I bought..left it in the shed all winter, never drained the fuel ( did not know about the effects of the 2T oil ) and come spring, no way would it start..took it back to the dealers more than a bit miffed about a new strimmers not starting ..but he just asked had I drained it after using it last season. And he then educated me in the vagaries of petrol engines in general , and 2 T oil in particular. I never made the same mistake again. He also warned me about petrol going "dead" when stored for a long time. The mower has been idle for a few months now, but when I start using it again, I'll add some aditive to the tank to "rejuvenate " it again.
I'd say that you wont be the only one changing their motoring habit's this year. And for sure anyone doing that kind of mileage, an EV makes sense.

ml100

jmreire wrote: »

The strimmer will be fine, once the fuel pipes are either replaced, and the carburettor cleaned... and there are cases too where they start after a few pulls, and work away. I learned the hard way with a new strimmers I bought..left it in the shed all winter, never drained the fuel ( did not know about the effects of the 2T oil ) and come spring, no way would it start..took it back to the dealers more than a bit miffed about a new strimmers not starting ..but he just asked had I drained it after using it last season. And he then educated me in the vagaries of petrol engines in general , and 2 T oil in particular. I never made the same mistake again. He also warned me about petrol going "dead" when stored for a long time. The mower has been idle for a few months now, but when I start using it again, I'll add some aditive to the tank to "rejuvenate " it again.
I'd say that you wont be the only one changing their motoring habit's this year. And for sure anyone doing that kind of mileage, an EV makes sense.

Unless you are using a serious amount of 2 stroke buy a can if Aspen 2 lasts for a few years + much cleaner when using and inhaling and no mixing, no need to drain the tanks, I've been using it for a few years, works great!

https://robertkee.ie/product/aspen-2-pre-mixed-2-stroke-fuel-5-litre

jmreire

ml100 wrote: »

Unless you are using a serious amount of 2 stroke buy a can if Aspen 2 lasts for a few years + much cleaner when using and inhaling and no mixing, no need to drain the tanks, I've been using it for a few years, works great!

https://robertkee.ie/product/aspen-2-pre-mixed-2-stroke-fuel-5-litre

Well, it all depends on whats happening at the time, when its the chainsaw season, yes I'd be using quite a lot of 2T. And if you add in strimmers and blowers in season, 5 ltrs will not go far TBH. So I add whats in the pic ( the Red X is for diesel, but its available for petrol engines too.) and so far, no gelling or starting problems. I use the same filling station all the time,,,they have a high turnover, and the tanks are new. Ive heard of Aspen before and it seems to be a very good product too.

nophd08

+1 for Aspen. I've never used anything else. Yes more expensive but you use less of it and your engines will thank you for it.