Failed NCT high CO emissions

jenlen87

Hi all,
well my 2002 1.4 lt golf just failed its NCT today on emmisions. It failed on high idle(2750 rpm) CO 0.60 VOL% which is 3 times what it should be. any suggestions what it could be?? been reading about cat convertors etc and all sound so expensive. Been to the garage twice before the NTC to fix the front brakes and they also did the pre test so how would they have missed the emmissions?? I also got the car serviced in june as well prior to all this (in a different garage)so bit mad that its costing me so much. I have just moved here and know not a lot about cars so sometimes i wonder do they think because im a girl on my own i know no better. Want to give people the benefit of the doubt but would also like to know somethings before i go there so i dont look like an idiot.
So any help would be great thanks in advance
jen

zilog_jones

Don't these engines have a problem with piston rings? Does it burn oil? That could lead to high CO I guess.

franksm

Hmmm... I would challenge the garage that did a pre-test for a refund on the emissions reading at least :-/

But anyway, fix some basic servicing parts before assuming the expensive stuff (ie. the cat) is bad:

- replace sparkplugs
- replace air filter
- check all the rubber hoses around the engine-bay for leaks (use a stethascope or similar to check for hissing noises)
- check the exhaust system from end-to-end for leaks (might be noisy or you might see some soot marks around leaking parts). Be careful getting under the car

Replacing filter and plugs is DIYable, shouldn't cost more than 30 quid. Unless the garage had already done that for you of course...

Mr Will

Get some sti injector/engine cleaner and put it in the fuel tank.... give the car a good drive before retest to get engine good and hot... leave the car running whilst waiting for the car to be taken in...

wonderfulname

Rev the crap out of the car before you go in, its never failed me, completely defeats the purpose of that particular test but you pass.

jenlen87

Replacing filter and plugs is DIYable, shouldn't cost more than 30 quid. Unless the garage had already done that for you of course...[/QUOTE]

got all these done in june as it was burning oil would it be faultly already?? and there is not hope of me doing this myself would not know where to begin only time i miss my brothers thanks franksm

thanks mr will can you get that stuff from any good motor shop??

zilog_jones

If it's burning oil it probably is the piston rings so (16 valve engine?), and I don't think fuel additives will do much help in that case. It's a well known problem with VW 1.4 16V engines from that era, and it's shocking they never did a recall.

jenlen87

zilog_jones wrote: »

If it's burning oil it probably is the piston rings so (16 valve engine?), and I don't think fuel additives will do much help in that case. It's a well known problem with VW 1.4 16V engines from that era, and it's shocking they never did a recall.

It was burning oil in june but got the air filter etc done and its not now. Is it a big job to get the piston rings replaced? Just dont want the garage to rip me off

zilog_jones

Maybe it was just the wrong oil in it before or something. It is a pretty big job, not sure how much it'll cost but I'm sure there's some garages who are well used to doing it. There must be someone around here with more experience on the subject...

itarumaa

I think that if the engine is burning oil, it should be visible in the HC value and not CO value,

based on my experience anyway.

jenlen87

just been to the garage told them i was not happy they missed it in the pre test. He took one look at the piece of paper from the nct and said it was the sensors asked him how he knew that from a piece of paper said just it had to be that!! Waiting to find out how much its going to cost thinking of taking it home to my cousin to sort out thanks to everyone who posted helpfull advice at least i knew something bout the car when i went in think he was taken aback by my knowledge of what he was talking about. will let know how it goes thanks again jen

MrMarsh

jenlen87 wrote: »

just been to the garage told them i was not happy they missed it in the pre test. He took one look at the piece of paper from the nct and said it was the sensors asked him how he knew that from a piece of paper said just it had to be that!! Waiting to find out how much its going to cost thinking of taking it home to my cousin to sort out thanks to everyone who posted helpfull advice at least i knew something bout the car when i went in think he was taken aback by my knowledge of what he was talking about. will let know how it goes thanks again jen

Jenlen,

A common problem with the MK4 Golf 1.4 unfortunately and not a cheap one to get fixed either. The problem is the valve stem oil seals. They perish with time and this allows engine oil to seep into the pistons and be burned off causing an NCT fail in both CO2 and smoke levels. Depending on how bad it is it may result in the lambda sensor being cocked up with carbon and also the cat becoming useless from the build up of oil. You're looking at a bill of around €250 for replacing the seals on their own as it involves the engine being stripped and rebuilt with a new head gasket. At the same time you would be wise to fit an new timing belt, tensioners and water pump, probably another €250. Then with all that done you may have to replace the lambda sensor and cat at a cost of, you guessed it, about €250. I'd trade it in if I were you, unless finances prevent you from spending a couple of thousand.