Tips on NCT Emssions Failure

Frank_Leach

HI folks..
just failed nct for second time today, on bloody emissions, once again! i don't pretent to know a whole lot about these things, so i will try explain as simply as possible, and i hope some kind soul might offer imput in a simple manner too!

So, the results: First time...

Low Idle (710rpm) CO .28% PASS
High Idle (2750rpm) CO .70% FAIL
LAMBDA 1.015 (Between .97 - 1.03,) PASS.

In summary, high idle failed. Since then, it was suggested to me to run engine cleaner through the petrol, which i did. Two bottles of redex, and half a bottle of the rather expensive Lucas upper cylinder lubricant. Felt alot better to drie, but those pasky folk at the nct centre had other ideas.

Second time(Today)

Low Idle (710rpm) CO.28% PASS-SAME RESULT AS BEFORE.
High Idle (2750rpm) CO.51% FAIL - THOUGH IMPROVED ALOT
LAMBDA 1.012 (bETWEEN .97 - 1.03) PASS, AND SLIGHTLY IMPROVED.

I read a few posts here already, cant say i found my answer, but i did see that any previous exaust damage could be a factor? there was a hole in the exaust when i got it, i had it welded to stop the noise. from what i remember, it was a smallish hole and was simply covered.

Any feedback welcome guys, as you all know, i am on my last shot here, otherwise i have to get full retest......and, knowing my bloody luck it'll fail on new things by the time that coomes around...

One last thing...someone was telling me of a trick to get around this emissions prob short-term....something about an alcohol solution through the airfilters or something? yes, i know nothing, i am in need of wosdom today...much thanks!!

Matt Simis

No need to post that twice. Assuming you car was made post 1987, I would try 15% E85 on top of your regular fuel and drive it till hot before getting there.

Does anyone here know how the NCT Lambda test result is derived? The HC and CO emissions are presumably actual emissions from the exhaust picked up by the "sniffer". The Lambda however is a car part, how is that figure got to?

Muckie

Hi lads i'd recommend pouring some Diptaine into your tank, a few miles

from the test centre. Drive a Subaru myself(also has a modified back box),

failed emissions first time, replaced the O2 sensor and add the Diptaine.

flew thru after that. So theres still hope of passing folks!

Rowley Birkin QC

Diptaine?

My car failed it last time for a few issues including a leaking exhaust so they didn't test emissions. Are the general tips just to give the car a good ragging before bringing it for the test or is there anything more specific to having it in top shape for the emmissions?

Muckie

Yep. Diptaine, did the trick for me.

Didnt need to rev the daylights out of the engine, just poured in a bottle

of the stuff into a half tank a few miles from the centre. Car flew the

test after that. Improved preformance of the car too.

Rowley Birkin QC

Any other opinions on this Diptaine stuff?

How much is it anyway?

Muckie

Far as i can remember it was around €10. Litre bottle i got from my

local motor factors. There some other stuff called "Cataclean".

Does the same job. It comes highly recommended by Car Meganics magazine.

Rowley Birkin QC

Yeah it seems to be legit having looked at the website.

List of stockists here.

Seems its called Dipetane.

Muckie

Your in business so, worth a go.

gline

i use Dipetane every few months, its great and does make a difference in smoothness of the drive aswel

danie29

I have a 96 fiesta which pupms out fuems but i just replaced the lambda sensor itself and think it worked, have another nct in a few days. lambda can brake fairly easy and this controls your emmisions

Frank_Leach

Muckie wrote: »

Yep. Diptaine, did the trick for me.

Didnt need to rev the daylights out of the engine, just poured in a bottle

of the stuff into a half tank a few miles from the centre. Car flew the

test after that. Improved preformance of the car too.

Diptaine is certainly a help-my 97 Mitsubishi Lancer failed on emissions too, and while liberal doses of Diptaine did reduce the percentages, it did not do enough and the car still failed on emissions.
I had to get the catalytic converter done, an unfortunate expense of 300 euro.
On this very thread, a mechanic from the nct centre writes about this problem, and bottom line is, fuel cleaners will do only so much. I still use Diptaine, as i know it is good for cleaning the injectors etc. But emissions failings, if it's bad enough, no engine cleaner will get you through.

Frank_Leach

Muckie wrote: »

Hi lads i'd recommend pouring some Diptaine into your tank, a few miles

from the test centre. Drive a Subaru myself(also has a modified back box),

failed emissions first time, replaced the O2 sensor and add the Diptaine.

flew thru after that. So theres still hope of passing folks!

no offence, but was it more to do with the o2 sensor than the diptaine?
What was the readings?

danie29

just passed nct today put a bottle of (Nitrox Hot Shot 500ml in halfords) in with 20euro petrol, failed first time with emmisions of 0.49 after hot shot passed with readings of 0.05.

Frank_Leach

danie29 wrote: »

just passed nct today put a bottle of (Nitrox Hot Shot 500ml in halfords) in with 20euro petrol, failed first time with emmisions of 0.49 after hot shot passed with readings of 0.05.

Can you tell us the make, model and year of car?
That's pretty impressive...so a bottle of this stuff into a half tank of petrol?

Congrats...result!

danie29

its a 96 ford fiesta ya worked wonders for me, felt a bit of extra power aswell.

-Corkie-

Frank_Leach wrote: »

Diptaine is certainly a help-my 97 Mitsubishi Lancer failed on emissions too, and while liberal doses of Diptaine did reduce the percentages, it did not do enough and the car still failed on emissions.
I had to get the catalytic converter done, an unfortunate expense of 300 euro.
On this very thread, a mechanic from the nct centre writes about this problem, and bottom line is, fuel cleaners will do only so much. I still use Diptaine, as i know it is good for cleaning the injectors etc. But emissions failings, if it's bad enough, no engine cleaner will get you through.

Advance pitstop should sort that out