Failed NCT because of high CO emissions! :(

py2006

Hi folks,

The aul car failed the NCT this morning. Everything else was fine apart from the high emissions.

The dude said it was from revving the engine too much! I don't think I do that at all to be honest.

What do I need to do next? How much do you think it will cost to fix?

Thanks

Hellrazer

Throw a couple of tins of injection cleaner in the tank and put it through again.Try run it so the tank is about quarter full and try 2 tins of BG products 44k.
From my experience its usually good for getting past the emissions tests.

BrianD3

More detail please, what does the white sheet that the tester gave you say about Emissions. Post the levels etc. Also what year is the car.

Mr Magnolia

Injector cleaner & rev' the shoite out of the engine on the way down to the next test, this gets rid of any build up of soot/smoke etc in the exhaust system. Also, make sure the engine has had a good drive before the test and is well warmed up.

If the car hasn't been serviced recently you may need to do it. Oil change, oil filter, air filter.

If it's a diesel car you could lob a gallon of kerosene into a near full tank of diesel, this will reduce emissions - don't know the legality of this though (but, if you are dipped this small amount will be unrecognizable as Kero is yellow/clear)

I think the re-test is €25-€30, they'll only check emissions if that's all that was wrong with it the first time once your within assigned time allowed (28 days I think)

Give more details on the car and I might be able to help further.

It would be useful to know what kind of car you drive OP

py2006

BrianD3 wrote:

More detail please, what does the white sheet that the tester gave you say about Emissions. Post the levels etc. Also what year is the car.

I'm in work at the moment but I will post the details later. The car is a 99D.

py2006

ronoc wrote:

It would be useful to know what kind of car you drive OP

99D 1830cc Mazda MX5 (Import)

Nearly 2 years since its last service! :O

py2006

Sparks400 wrote:

Injector cleaner & rev' the shoite out of the engine on the way down to the next test, this gets rid of any build up of soot/smoke etc in the exhaust system. Also, make sure the engine has had a good drive before the test and is well warmed up.

If the car hasn't been serviced recently you may need to do it. Oil change, oil filter, air filter.

If it's a diesel car you could lob a gallon of kerosene into a near full tank of diesel, this will reduce emissions - don't know the legality of this though (but, if you are dipped this small amount will be unrecognizable as Kero is yellow/clear)

I think the re-test is €25-€30, they'll only check emissions if that's all that was wrong with it the first time once your within assigned time allowed (28 days I think)

Give more details on the car and I might be able to help further.

Thanks, its not a diesel. It is a 99 D MX5 Jap Import. Apparently my emissions were .4 or something like that. I will have to check the thingy your man gave me afterwards.

Lex Luthor

I thought the emissions on the NCT were CO, not CO2...obviously they are related but the CO value is normally 0.X where the CO2 value is usually quoted in kg/m3

Mr Magnolia

py2006 wrote:

99D 1830cc Mazda MX5 (Import)

Nearly 2 years since its last service! :O

There's your problem right there.

py2006

Lex Luthor wrote:

I thought the emissions on the NCT were CO, not CO2...obviously they are related but the CO value is normally 0.X where the CO2 value is usually quoted in kg/m3

You could be right. I will have to wait till I get home later this evening to check it out! I think it read 0.4 anyway!

JHMEG

Yeah, it's CO, not CO2. Either your cat or your O2 sensor are most likely fooked.

py2006

JHMEG wrote:

Yeah, it's CO, not CO2. Either your cat or your O2 sensor are most likely fooked.

Well Mr. NCT said it was from revving the engine to much?

Lex Luthor

py2006 wrote:

Well Mr. NCT said it was from revving the engine to much?

then we're all fooked

JHMEG

py2006 wrote:

Well Mr. NCT said it was from revving the engine to much?

Yeah, you've blown the inside out of the cat all over the road.

Mr Magnolia

py2006 wrote:

Well Mr. NCT said it was from revving the engine to much?

The high emissions were caused by him rev'ing the engine too much, this caused plumes of smoke out the exhaust registering high emissions. You need to rev the car a bit before you go into him next time to blow some of the build-up out of it.

Start with the service

JHMEG

Sparks400 wrote:

The high emissions were caused by him rev'ing the engine too much, this caused plumes of smoke out the exhaust registering high emissions. You need to rev the car a bit before you go into him next time to blow some of the build-up out of it.

Start with the service

Smoke is not equal to CO. :rolleyes:

py2006

Sparks400 wrote:

The high emissions were caused by him rev'ing the engine too much, this caused plumes of smoke out the exhaust registering high emissions. You need to rev the car a bit before you go into him next time to blow some of the build-up out of it.

Start with the service

I will do thanks! But I don't think I rev the engine all that much to be honest!

Mr Magnolia

py2006 wrote:

I will do thanks! But I don't think I rev the engine all that much to be honest!

read it again my friend. You need to rev the car to get rid of the build up

py2006

Sparks400 wrote:

read it again my friend. You need to rev the car to get rid of the build up

ahhhhhhhhhh, the penny drops!

unkel

Sparks400 wrote:

You need to rev the car to get rid of the build up

Was driving up and down the N4 doing 80km/h in second gear in the Rover 75 yesterday. Passed the NCT

Last time I did the same in the BMW but I was doing 80km/h in 1st gear :eek:

Mr Magnolia

JHMEG wrote:

Smoke is not equal to CO. :rolleyes:

When I say smoke I mean emissions in general which are made up of CO/HC/Lambda from NCT

and ease off on those *rolleyes*

EDIT/ just seen Unkel's post - lol

antodeco

Just stick an old tshirt in the exhaust and push it up with a broom!! That'll temporary fix it!

JHMEG

Sparks400 wrote:

When I say smoke I mean emissions in general which are made up of CO/HC/Lambda

Revving the stones out of a car cleans out the soot, and is a common practice to clean out diesels as a smoke test is part of the NCT for diesels. A smoke test is not part of the NCT for petrol engines.

Revving the stones won't fix a broken cat or sensor, which affect CO and HC emissions.

Lambda isn't an emission:rolleyes: It's a measure of oxygen content, and in the context of the NCT is used to verify the exhaust system is not leaking.

BrianD3

I agree with the last post. There's too much emphasis in this thread on "revving the bollox out of it" as a cure for failing the NCT emissions.

To be honest, if the car is failing on CO I would be inclined to bring it to a diagnostic specialist like Mr.Diagnostic who posts here on boards I know of too many people who put themselves through unnecesesary hassle turning up for emissions retests havng "revved the bollox out of it" thinking that will get the car to pass. When the car still fails they've wasted the cost of the retest and the car still isn't right. They then moan about how the NCTS are a shower of ****.

py2006

Ok, so I have the NCT report here in front of me.

CO is 0.47% on High Idle

BrianD3

What's the engine/oil temperature?

TBH you have failed the CO by a fair margin there. Limit is 0.3%

JHMEG

Well, after you get it serviced you can either

a) rev the stones out of it, or
b) bring it to someone to have the cat and sensors diagnosed

before you bring it for the retest!

Altreab

JHMEG wrote:

Well, after you get it serviced you can either

a) rev the stones out of it, or
b) bring it to someone to have the cat and sensors diagnosed

before you bring it for the retest!

OR
better still
a) bring it to someone to have the cat and sensors diagnosed

THEN

b) rev the stones out of it

Check it still has a cat converter.
Lots of jap imports are decatted for performance reasons.

Mr Magnolia

JHMEG wrote:

Lambda isn't an emission:rolleyes: It's a measure of oxygen content, and in the context of the NCT is used to verify the exhaust system is not leaking.

If it's emitted from the exhaust it's an emission. I had a car fail on this high lambda (as you pointed out) due to a small hole further back in the exhaust system.

Mr.Diagnostic

Sparks400 wrote:

If it's emitted from the exhaust it's an emission. I had a car fail on this high lambda (as you pointed out) due to a small hole further back in the exhaust system.

But it is not emitted from the exhaust.


The first thing to remember about emissions based on info from an NCT cert is that the NCT machine only shows and prints half the info required to form an opinion.

Mr Magnolia

Mr.Diagnostic wrote:

But it is not emitted from the exhaust.

Ok, still not clear to me what the measure of lambda is:o I thought it was too much air being exausted, is this just a resultant?

craichoe

Jesus H, just go get the car serviced.

High CO emissions could be any number of reasons and "Mr NCT" is just guessing. They'll need to bring it in and check various components.

Could be:
1. A Shattered CAT
2. Dirty/Malfunctioning Air Flow meter

P.S. Not getting your Car serviced for 2 years is just asking for trouble, regardless of mileage, do you even know when your timing belt was last changed !

JHMEG

Mr.Diagnostic wrote:

But it is not emitted from the exhaust.

sparky400 wrote:

Ok, still not clear to me what the measure of lambda is I thought it was too much air being exausted, is this just a resultant?

Air coming through a hole in the exhaust does not qualify as "emissions"!!:rolleyes:
What comes from the engine exhaust (thru the cat) are emissions.

Mr.Diagnostic

Sparks400 wrote:

Ok, still not clear to me what the measure of lambda is:o I thought it was too much air being exausted, is this just a resultant?

It is not a measurement, it is a calculated value. The calculation happens in the gas analyser. All of the exhaust gasses can effect the lambda value. Exhaust gas analysis is quite a complicated subject. If you are interested enough you could google "Brettschneider equation".

This is unlikely to help the OP much though. Best advice would be to get it serviced, 2 years is way too long, and get the garage to check gasses after.

Mr.Diagnostic

JHMEG wrote:

Air coming through a hole in the exhaust does not qualify as "emissions"!!:rolleyes:
What comes from the engine exhaust (thru the cat) are emissions.

I suppose it depends on what your defination of "emissions" is. Anything that comes out the exhaust is emissions in my book.
I posted in answer to Sparks who said that Lambda was emitted from the exhaust.

MAYPOP

craichoe wrote:

Jesus H, just go get the car serviced.

end of.

JHMEG

Mr.Diagnostic wrote:

I suppose it depends on what your defination of "emissions" is. Anything that comes out the exhaust is emissions in my book.

Well, I suppose fair enough. I would consider anything that comes out of the engine and through the emissions control system (cat being last part) to be emissions. But I wouldn't classify air drawn in thru a hole in the exhaust pipe and coming out the tailpipe to be emissions.

Either way the OP needs to get a service and get the car diagnosed. Revving the stone is not gonna help in my opinion.

Mr Magnolia

Mr.Diagnostic wrote:

It is not a measurement, it is a calculated value. The calculation happens in the gas analyser. All of the exhaust gasses can effect the lambda value. Exhaust gas analysis is quite a complicated subject. If you are interested enough you could google "Brettschneider equation".

Perfect, question answered.

Thanks Mr.Diagnostic.

Mr Magnolia

JHMEG wrote:

Revving the stones out of a car cleans out the soot, and is a common practice to clean out diesels as a smoke test is part of the NCT for diesels.

JHMEG wrote:

Either way the OP needs to get a service and get the car diagnosed.

Agree totally, off to the Garage with ya OP....


Post #4

Sparks400 wrote:

Injector cleaner & rev' the shoite out of the engine on the way down to the next test, this gets rid of any build up of soot/smoke etc in the exhaust system. Also, make sure the engine has had a good drive before the test and is well warmed up.

If the car hasn't been serviced recently you may need to do it. Oil change, oil filter, air filter.

Let us know how you get on

py2006

Will yiz relax! I will make inquiries in the next day or so re Service. I will let yiz know how I get on.

Anybody wanna buy an MX5?

Wossack

py2006 wrote:

Will yiz relax! I will make inquiries in the next day or so re Service. I will let yiz know how I get on.

Anybody wanna buy an MX5?

FSH?

theAwakening

i have a performance exhaust on my car. it a dual tip one. will i fail on emissions do ye think?

apologies if thats a stupid question.