NCT emissions failure question...

unklerosco

Failed on CO and H**(can't remember exactly)...

Roughly, what cause's emissions failures?? I'm thinking catalytic converter but i'm hoping it aint as a new one would prob cost more than the cars worth...

astraboy

Could be a lamba sensor. This is a sensor in the exhaust manifold(or close to it) to measure the exhaust gasses and adjust the fueling accordingly. I needed to replace mine for the NCT, costs about 100E.

Also, it may be dirty injectors, you can buy fuel additives that will clean these out.

It may be a hole in the exhaust or manifold, putting off the lamba sensor and therefore giving the poor readings.

Finally, as you said, it may be the cat. What age/make/model is your car?

unklerosco

99 fiat brava(1.2 16v)

Is there any way of finding out what it is??

sc4rf4ce

is there a strong smell of petrol coming from the car when idle, or rotten eggs after a few mins of driving?

unklerosco

nope...

Cosmo K

Forget about fuel additives, waste of money. Bring it to garage that has an emissions tester and a diagnostic computer, no point in just guessing whats wrong with your car.

Avns1s

sc4rf4ce wrote: »

is there a strong smell of petrol coming from the car when idle, or rotten eggs after a few mins of driving?

What would that indicate?

unklerosco

Cosmo K wrote: »

Forget about fuel additives, waste of money. Bring it to garage that has an emissions tester and a diagnostic computer, no point in just guessing whats wrong with your car.

I'm thinking thats my only option.... Bit of a pain as i only want to NCT it to sell it??

Any ideas what a 99 brava with no nct would go for??

It failed on

High idle 2630rpm
CO .56% above .3% fail
HC 220ppm above 200ppm fail

It passed the low idle 770rpm

alias no.9

Did you fail badly or was it marginal? Has you done a lot of stop start driving in heavy traffic without really getting up to speed in the days before the NCT? If so, it may just need an italian tune up, i.e. once the engine is warm, take it out and thrash it for about 10 minutes. If the engine has got a bit coked up, this will burn off the carbon deposits. Other than this, when were the spark plugs last changed?

unklerosco

Car hadn't been drivin for about 2 weeks before the NCT, and then it was only drivin for about 15mins to get to the center...

Results are above, no idea if they'er way off....

Cosmo K

I agree with alias no.9, its only slightly above the limits, so a new set of plugs+the italian Tune up might do the job.....


.............italian tune up, never heard that before.....nice one:D

sc4rf4ce

Originally Posted by sc4rf4ce
is there a strong smell of petrol coming from the car when idle, or rotten eggs after a few mins of driving?

that would indicate that the cat converter has had its day.

unkel

Yup as the lads said. You only just failed it. Drive the car hard for 15 minutes just before the re-test. I bet ya it will pass!

alias no.9 wrote: »

an italian tune up

LOL, a bit like an italian shower

unklerosco

Yep, mechanic said the same thing.... Will give it a go, sure its cheaper than getting it into a garage

Esel

I do Italian tune-ups, at your own risk of course! :eek:

JHMEG

Cosmo K wrote: »

its only slightly above the limits,

It may be only slightly over the limits, but it's waaaayyyy above where it should be. No amount of Italian tuning is gonna fix that. Tho it might blow the cat out onto the road, which will add a few bhp (but still fail the NCT).

BrianD3

I also don't think this Italian tune up is going to work in this case. The CO is 0.56 which is nearly double the limit of 0.3. IME a car with a functioning catalytic converter/lambda sensor etc. should sail through the CO high idle test and get a result of 0.05 or less. That's 10 times less than the original poster's car achieved. I can't see the car passing the retest but hopefully it does, let us know how you get on anyway.

Cosmo K

Tho it might blow the cat out onto the road, which will add a few bhp (but still fail the NCT).

So what? If the cat is already gone, it will make no difference, and if he fails again, he needs new cat anyway. Well worth a try.....but I know,he should have bought a Honda.....

JHMEG

Cosmo K wrote: »

So what? If the cat is already gone, it will make no difference, and if he fails again, he needs new cat anyway. Well worth a try.....but I know,he should have bought a Honda.....

Well as long as the OP doesn't mind the time and expense required to do all these NCTs...

My advice would be to take the 50 euro and instead of doing another NCT just get a diagnostic done, which he's probably going to end up doing anyway.

greglo23

What temp was it tested at ? Due to the recent cold weather the engine temp may not have been high enough for the emissions test! For most modern cars they have to be above at least 80 degrees before the test even begins to give it the best chance of passing.

Jeapy

My boyf is havin the same problem. Has failed the test twice now and the mechanic in the garage he bought it told him that the car has started burning oil and will cost at least 600 euro to fix. he tried the "italian tuning" thing and a friend of his who is a mechanic did some work (cost 200 euro) and still no good! he only bought the car a few months ago! :mad:

Cosmo K

What temp was it tested at ? Due to the recent cold weather the engine temp may not have been high enough for the emissions test! For most modern cars they have to be above at least 80 degrees before the test even begins to give it the best chance of passing.

Sorry, but thats nonsense. During the test the engine is revved up to 2500-3100 rpm for 210 sec. Thats plenty of time to get the engine up to at least 80 C. And I don't think he lives right beside the NCT center, or pushes the car all the way from his place to the NCT, so the engine should be warm enough when he arrives.

@JHMG

Of course it would be a good idea to have the emmissions checked before he brings the car back in, trouble is though, most garages charge a small fortune for a diagnostic check+emmissions test.
If they have an emmisions tester.......

BrianD3

Cosmo K wrote: »

most garages charge a small fortune for a diagnostic check+emmissions test.
If they have an emmisions tester.......

A lot of the small independent garages do now have exhaust gas testing equipment and charge about 30-50 quid for the test. Of course the gas test is no good unless they know how to interpret the results...

JHMEG

BrianD3 wrote: »

A lot of the small independent garages do now have exhaust gas testing equipment and charge about 30-50 quid for the test.

Which is about the price of an NCT! (But eliminates the guesswork)

greglo23

Cosmo K wrote: »

Sorry, but thats nonsense. During the test the engine is revved up to 2500-3100 rpm for 210 sec. Thats plenty of time to get the engine up to at least 80 C. And I don't think he lives right beside the NCT center, or pushes the car all the way from his place to the NCT, so the engine should be warm enough when he arrives.


I'm afraid your making a few assumptions here. If his car was tested immediately he arrived at the centre which is very rare then it may be up to temp. A cool engine sitting in a cold breeze will lose heat rapidly. If his thermostat is not working properly then his journey of 15 minutes will have barely warmed up the car unless he spent most of his time sitting in traffic.
An example is a lot of older Escorts which had to be at least 90 degrees before they would pass!

Cosmo K

they know how to interpret the results...

And thats exactly the problem. A lot of mechanics out there simply still don't know what to do, if a car fails the NCT on emmisions. They are guys out there, who still change Lambda sensors, because the car failed on a bad lambda reading.

Lets say, they charge 50 for the emmisions check, and another 50 for the diagnostic check, then 27.50 for the ReTest+20 for a set of plugs is still the cheaper option.
Driving car the car hard for 15 min might just do the trick. Another option is to rev it up to 4000 rpm for 2 min, but you want to keep an eye on the temp gauge if you do that....espec if its FIAT:D:D

windsurfer99ie

As engines get older their emission performance generally gets worse (like some people).
My cars have failed on emissions on several occasions - generally (if it isnt too bad) a garage will adjust the carb (weaken the mixture) to get you through. This is OK because they are only adjusting the mixture at idle.

There are several possible reasons for more catastrophic failure including Oxygen Sensor / worn engine / electrical problems. Unless the emissions are way off the scale you should be ok...

zilog_jones

windsurfer99ie wrote: »

My cars have failed on emissions on several occasions - generally (if it isnt too bad) a garage will adjust the carb (weaken the mixture) to get you through. This is OK because they are only adjusting the mixture at idle.

Carbs?! How old are your cars?

Esel

zilog_jones wrote: »

Carbs?! How old are your cars?

About as old in years as this thread is in days.