NCT fail high emissions, any tips to reduce?

madmaxvideo

Hi guys, my '99 vw golf 1.4 petrol failed NCT on high emissions. Results: high idle Lambda 1.10 CO 0.44 vol% HC 202ppm. The tester suggested it was cat. converter, just looking for some advice/ tips to reduce before I spend a small fortune replacing the cat?

Ken Tucky

Feel your pain, had a 1.4 bora 99 and put it through 3 time before i got the cert. I replaced the cat but still didnt pass. Think they took pity on me in the end. Its a load of balls failing a car on emmisions.
Supposedly the 1.4 engines have this issue.
Have you tried dipetane and getting the engine fired up just before you arrive for the test.
I would start with the small stuff before you replace the more expensive parts.
just my experience with it though, im no mechanic.

V.W.L 11

Ken Tucky wrote: »

Feel your pain, had a 1.4 bora 99 and put it through 3 time before i got the cert. I replaced the cat but still didnt pass. Think they took pity on me in the end. Its a load of balls failing a car on emmisions.
Supposedly the 1.4 engines have this issue.
Have you tried dipetane and getting the engine fired up just before you arrive for the test.
I would start with the small stuff before you replace the more expensive parts.
just my experience with it though, im no mechanic.

Had a 1.4 bora fail the emissions with an entire bottle of dipetane in the tank in July,1.4 vw engines are sh1t

madmaxvideo

Yeah, it's a pain in the rear end, these engines seem to be notorious for burning oil, not sure with these readings if it is excessive, or something to be worried about. Is there anything to buy that can read emissions at home? Rather than paying a garage every time I try something?

Ken Tucky

Nope and the poxy thing is, even if a garage gets the readings under the limit that dosent mean the NCT center will get the same result off their machine.
I,d get it through this time and get rid. Just have a melt down with them
ask them just what the **** they want you to do as you could easily spend the value of the car tring to get a remedy for this
Could happen a year later again. Headwrecking stuff really

madmaxvideo

I know all too well with the NCT, had a car fail on head light alignment, had a garage adjust them, returned to NCT to be failed again, had to get print out from main dealer to confirm light alignment was ok and when I returned to NCT they passed it without re-testing it!! Hope to get it through and sell it on after xmas. I'll start with the fuel additive first and take it from there. Here's hoping!!!

hi_im_fil

First thing is your lambda reading is off which will mean all the other readings will be thrown off. Try find the cause of the lambda failure, if you fix that then all the others should fall more into line.

Lambda is basically the air/fuel ratio. 1.1 means excess air was measured by the nct testers probe. Are there any intake or exhaust leaks?

George Dalton

As above. Forget the CO % for the moment. Sort out the lambda reading first and then see where you stand.

madmaxvideo

Thanks George, I'd like to understand the readings, which should help diagnose the problem!! As far as I know there is no intake/ exhaust leaks. It was suggested to remove the air filter as well as a petrol additive, should reduce emissions. Would a faulty lambda sensor give these readings?

Titzon Toast

You could maybe also try decarbonisation of the engine and fuel system. It's a little pricey, but it looks like a great process. I'm planning on getting it done to my own car as soon as I have some spare cash.

derry

The CAT is downstream and rarely the problem .

Consider to change to special low pollution types fuel for the day of tests cost €5 a liter but sick dogs can pass emissions with clean burn fuel

TBH There isnt so many bad reports about the Bora in mainland Europe so it is probably the toxic fuel the oil companies serve us in Ireland that Boro cant deal with

Ask the fuel stretch victims who bought from reliable main dealers and not cheap scum bag operators who got their engines wrecked

I would start with upstream the fuel first try batch of fuel from UK and bet the car passes no problem

Derry

L-M

I had one for three years that was always over on the emissions.

A bottle of diptane 5 days before the test, and give it a good drive. Before the test I used to go out and back the motorway in 3rd gear and literally rev the ****e out of it. (Not off the limiter, obviously).

Never failed me after that.

madmaxvideo

Hi lads, I've been using diptane in the car the last week or so, have the retest tomorrow. In your experience would diptane reduce emissions to a passable reading, ie: reduce high idle lambda from 1.10 to under 1.03 and CO from 0.47% to below 0.30%.?Not sure if my readings are excessively high. Any feedback would be great.

MintyMagnum

I second the drive the sh"t out of it b4 test. Got that tip & never failed a test on emissions. Heard the additives can actually be worse. Also stop up b4 u get to test centre & rev the hell outta it while stopped, cleans it out Works for me!

jimgoose

What way are the plugs? Also, look for leaks in the exhaust headers between the manifold and the Lambda sensor.

madmaxvideo

Also failed to mention that it was tested on high idle at 97*c, but I drove about 16km to the test center, normal driving!!

madmaxvideo

Thanks for the quick replys, goes without sayin it will be all 2nd 3rd gears on the drive to nct tomorrow, haven't checked the plugs, would changing these make any difference?

jimgoose

madmaxvideo wrote: »

Thanks for the quick replys, goes without sayin it will be all 2nd 3rd gears on the drive to nct tomorrow, haven't checked the plugs, would changing these make any difference?

According to those emissions figures, you've got lots of oxygen, hydrocarbon (unburnt fuel) and carbon monoxide (fuel partially/insufficiently burnt) in your exhaust gas. This suggests to me that the oul' plugs might be old and/or past it, or that the exhaust manifold is drawing air through a leak upstream of the Lambda and buggering things right up.

Titzon Toast

Titzon Toast wrote: »

You could maybe also try decarbonisation of the engine and fuel system. It's a little pricey, but it looks like a great process. I'm planning on getting it done to my own car as soon as I have some spare cash.

Waste of money. Especially on a car fit for scrap.

Sam Kade

The lads selling the HHO snake oil conversions say that it lowers emissions but I would have to see proof first

L-M

madmaxvideo wrote: »

Thanks for the quick replys, goes without sayin it will be all 2nd 3rd gears on the drive to nct tomorrow, haven't checked the plugs, would changing these make any difference?

Take them out and clean them at least but make sure and rev her high going to the test! You don't need to speed you just need high revs.

zapata

Well OP - How did you get on?

madmaxvideo

zapata wrote: »

Well OP - How did you get on?

Well lads, let's just say they are absolute idiots in the test centre!! I arrived 5 mins late for my appointment and they were first not going to test it then one of the foreign guys said they would. After me driving the whole way at nearly constant 5000 revs!! They left the car sitting at the end of the lane for just under the hour before they tested it, a few people waiting aswell thought there was something wrong with the car as it was left there so long!! Tested at 84oC compared to 97oC on last test. Anyway it failed again on lambda, no change at 1.10 however the co and that were well below , diptane and cleaning plugs done the job for them. Now I'd say there is a leak in the exhaust or manifold somewhere. Thanks for all the help lads, keep any tips or tricks coming though!!

vandriver

You arrive late,and they are idiots?

madmaxvideo

vandriver wrote: »

You arrive late,and they are idiots?

10 mins grace with all nct centres, no? And then to make it worse for them two people got free nct due to it being over 60 mins!! So ye they are idiots.

vandriver

The Nct people recommend you arrive 10 minutes early.

madmaxvideo

vandriver wrote: »

The Nct people recommend you arrive 10 minutes early.

Fair enough vandriver! We'll leave it there.

It was suggested to me that there could be a hole in the exhaust system taking in excess air, could this be a possibility lads? Just don't want to go to the expense of buying cat. converters etc and spending a fortune and all it needed was a hole patched in the exhaust. Any ideas if the hole would be before the lambda sensor or after? For the experienced lads where would your next port of call be?

Anjobe

High lambda with all other levels OK could well be an exhaust leak. Possibly upstream from the sensor as your lambda reading is really quite high.

jimgoose

Anjobe wrote: »

High lambda with all other levels OK could well be an exhaust leak. Possibly upstream from the sensor as your lambda reading is really quite high.

All the high Lambda reading from the NCT's gas analyser is telling you is that there's too much oxygen in the exhaust. The leak could be anywhere, but it is likely to be somewhere before the back-box and after the cat/middle-box, I'd say.

Waterson

OP I would highly recommend you take your car to a garage with a diagnostics tester and someone who knows how to use it. Scanning the vehicle is the quickest and easiest way to diagnose your problem. In these instances, live fuel trim data is indespensible. The lambda sensor can be tested for correct functioning by creating artificial lean/rich conditions etc etc. The CAT can be tested for functionality with saturation tests. But first off, visually inspect exhaust system from manifold to CAT for any leaks.

TomoBhoy

Limerick man wrote: »

I had one for three years that was always over on the emissions.

A bottle of diptane 5 days before the test, and give it a good drive. Before the test I used to go out and back the motorway in 3rd gear and literally rev the ****e out of it. (Not off the limiter, obviously).

Never failed me after that.

This completely