NCT failed on emissions

peace2804

Hi all,

I have a 98 golf 4 1.4 petrol that failed over emissions twice.

First time:
Lambda: 1.00
Co 0.42
HC 212 ppm

Then the engine was checked and cleaned (all pipes, switches....) an oil leak was discovered so the breather box was changed and I got these results:

Lambda 1.01
CO 1.02
HC 399 ppm

This is a huge jump, is there anything that can be done to fix this issue or you think it's linked to the engine and thus it's pointless since the car is too old and not worth the hassle?

Thanks all for your replies in advance.

Cycling Dumbasses

My mother has same car and had similar problem, it is the cat.

timmy4u2

Having assumed that you are satisfied that all things electric are in order regarding sensors maf cat etc I would buy a bottle of dipetane. Put about three times the stated amount into the petrol and take it for a good brisk spin.
Put more petrol in before the retest and go over the top again with the dipetane.
I have seen it work wonders and it is not cheating either.

Cosmo K

NCT tester here, forget about the Dipetane, it doesn't work! Most likely your car needs a new cat. Or a new engine. 1.4 Golfs are well known for giving trouble, is the engine burning oil? If so, I'd think about spending money on the car.

peace2804

Thanks all, oil isn't burning at all, I might change the cat, any ideas about the cost folks? I presume that changing engine would be expensive as well so changing car might the best solution for the long term.

jimgoose

peace2804 wrote: »

Thanks all, oil isn't burning at all, I might change the cat, any ideas about the cost folks? I presume that changing engine would be expensive as well so changing car might the best solution for the long term.

Before swapping the cat I'd be inclined to change the air-filter and put a treatment of BG44K or Redex through it. Cat aside, if it's not burning oil there couldn't be too much wrong with the thing.

timmy4u2

Cosmo K wrote: »

NCT tester here, forget about the Dipetane, it doesn't work! Most likely your car needs a new cat. Or a new engine. 1.4 Golfs are well known for giving trouble, is the engine burning oil? If so, I'd think about spending money on the car.

How do you reckon Dipetane will not work?
I have used it several time with excellent results.
Latest was a vectra turbo diesel. It returned 7.2 on first test. Two rounds of dipetane at returned 2.7 at retest.
Obviously it will not replace a cat....

Cleveland Hot Pocket

timmy4u2 wrote: »

How do you reckon Dipetane will not work?
I have used it several time with excellent results.
Latest was a vectra turbo diesel. It returned 7.2 on first test. Two rounds of dipetane at returned 2.7 at retest.
Obviously it will not replace a cat....

Dipetane/Redex works if it is just a buildup within the engine (or just it is old) - wont replace a cat but will reduce emissions.

NCT testers a lot of the time are not even mechanics so I would not trust anything that they say.

Mar4ix

actually to find out is that cat or not, better visit a garage for tests.

lil story. one my friend of friends car failed emissions on oul (00 one) subaru impreza 1.6 petrol car... brought over to diagnostics, after long revving and heating car, it performed acceptable emission for nct , but guy said, it has to be well hot when enters nct, as cat is on the way out ....

So i did , and passed nct with emissions at fraction of 0.3 % , and I informed owner that next nct wont pass nct , as cat is on the way out .... got replay ... there is no cat, as it was removed while ago ... :eek:

So , car has to be well maintained, regular oil change, make sure, there is no vacuum , air leaks , exhaust not leaking, a specially before lambda sensor , new sparkplugs (essential thing is - has to be correct ones) , and the rest of sensors. not too many of them which affects emissions though.

Also there is practice that if car has been driving on small revs, cat getting clogged, and no do its work, there is some solutions - like remove cat, and put in special liquid for overnight, then wash with pressure washer, performed good results... never done this myself though.

Toyotafanboi

timmy4u2 wrote: »

How do you reckon Dipetane will not work?
I have used it several time with excellent results.
Latest was a vectra turbo diesel. It returned 7.2 on first test. Two rounds of dipetane at returned 2.7 at retest.
Obviously it will not replace a cat....

what is 7.2 and 2.7 a measurement of?
if a car is heavly heavily failing on emissions it is an indication that there is clearly a problem with the engine and that repair work is needed. and by repair work not a bottle of €5 snake oil.

timmy4u2 wrote: »

Having assumed that you are satisfied that all things electric are in order regarding sensors maf cat etc I would buy a bottle of dipetane. Put about three times the stated amount into the petrol and take it for a good brisk spin.
Put more petrol in before the retest and go over the top again with the dipetane.
I have seen it work wonders and it is not cheating either.

3 times the stated amount? how did you come to that scientific quantity? why do product manufacturers who have invested tremendous amounts of time and money into a product state quantities for someone like you to just over-ride them because you know better? if 3 times the recommended quantity works three times as effectively, why not just throw the whole bottle in, or better yet just fill the whole tank with it... oh wait...

i've also wondered what the "drive it hard on the way to the test center" does for a car.

timmy4u2

Cleveland Hot Pocket wrote: »

Dipetane/Redex works if it is just a buildup within the engine (or just it is old) - wont replace a cat but will reduce emissions.

NCT testers a lot of the time are not even mechanics so I would not trust anything that they say.

Of course it works. It is designed to do so. It wasn't what they said it is what their read out said on the official test certificate.

boldspirit

I used a couple of quids worth of diesel in a full tank of petrol to give the engine a clean a day or 2 before the NCT worked just fine

Mar4ix

boldspirit wrote: »

I used a couple of quids worth of diesel in a full tank of petrol to give the engine a clean a day or 2 before the NCT worked just fine

never heard of that ... i know, that in older diesel car put petrol .. something 5 % to clear the system . .. but diesel in petrol ??? i think it would only produce smoke ... and way opposite effect.

Cosmo K

timmy4u2 wrote: »

How do you reckon Dipetane will not work?
I have used it several time with excellent results.

Your are talking about a diesel, the OP's car is a petrol. Fuel cleaners in general, not just Dipetane, work to a certain degree when used to reduce diesel emissions.
In 99% of the cases however, they do nothing for petrol engines. I have seen this over and over again. Petrol car fails on emissions, customer comes back for a re-test after a week, nothing done to the engine, just a treatment with Dipetane-car fails again. Honestly, we see this nearly every flipping day. Especially 1.4 Volkswagen engines, they are real stinkers. Talk to a proper mechanic, and he will confirm that.


Cleveland hot pocket

I'm not sure what your qualifications are, but I can assure you, that every NCT tester is a qualified mechanic. That doesn't mean are always right, and never make mistakes-same as in every other profession, from guards to pilots-but to say that a lot of testers aren't even qualified is simply wrong.

boldspirit

Mar4ix wrote: »

never heard of that ... i know, that in older diesel car put petrol .. something 5 % to clear the system . .. but diesel in petrol ??? i think it would only produce smoke ... and way opposite effect.

I had an old XR3I, wasn't going to pass the test on emissions. Worked in a petrol station that was infront of a ford garage asked the owner/head mechanic had he any suggestions and thats what he told me to do.

I didn't drive her hard for the day or two coming up to the NCT but put good mileage on her. On the day of the test filled the tank again with petrol.

the car passed

Cleveland Hot Pocket

timmy4u2 wrote: »

Of course it works. It is designed to do so. It wasn't what they said it is what their read out said on the official test certificate.

Are you agreeing or disagreeing with me? I think I'm missing something

boldspirit wrote: »

I used a couple of quids worth of diesel in a full tank of petrol to give the engine a clean a day or 2 before the NCT worked just fine

I used to do this in reverse on an old diesel golf I had to clean it out.

Cosmo K wrote: »

Your are talking about a diesel, the OP's car is a petrol. Fuel cleaners in general, not just Dipetane, work to a certain degree when used to reduce diesel emissions.
In 99% of the cases however, they do nothing for petrol engines. I have seen this over and over again. Petrol car fails on emissions, customer comes back for a re-test after a week, nothing done to the engine, just a treatment with Dipetane-car fails again. Honestly, we see this nearly every flipping day. Especially 1.4 Volkswagen engines, they are real stinkers. Talk to a proper mechanic, and he will confirm that.


Cleveland hot pocket

I'm not sure what your qualifications are, but I can assure you, that every NCT tester is a qualified mechanic. That doesn't mean are always right, and never make mistakes-same as in every other profession, from guards to pilots-but to say that a lot of testers aren't even qualified is simply wrong.

Of course it works, you can see it working. Use it and do a pre, during, and after emissions test and you will see an increase when it works and then a decrease. I've seen it work on many cars so I know it works.

My qualifications are irrelevant to this issue.
I saw ads for NCT testers and contacted the company to ask what qualifications were required, only to be told that Leaving Cert was sufficient. Now this was back a couple of years to be fair so maybe the new crowd has a different policy.

timmy4u2

Toyotafanboi wrote: »

what is 7.2 and 2.7 a measurement of?
if a car is heavly heavily failing on emissions it is an indication that there is clearly a problem with the engine and that repair work is needed. and by repair work not a bottle of €5 snake oil.



3 times the stated amount? how did you come to that scientific quantity? why do product manufacturers who have invested tremendous amounts of time and money into a product state quantities for someone like you to just over-ride them because you know better? if 3 times the recommended quantity works three times as effectively, why not just throw the whole bottle in, or better yet just fill the whole tank with it... oh wait...

i've also wondered what the "drive it hard on the way to the test center" does for a car.

I would have thought there was no reason to quantify what those figures represented, after all we are talking about emissions.
And the instance I gave referred to a diesel. Have a look at the NCT manual. It may become clear to you then as you are obviously unfamiliar with the system.

Who told you that a "heavy" emission falure is very obviously an engine failure that requires engine repairs.
If it was your mechanic I would change immediately.

Most emission failures are caused by external issues, Lambda and cat to name just two.
Neither of these issues require "engine repairs" just replacement of these external items.
A very bunged up air filter can have the same result. Again just a simple issue to replace the air filter. No "engine" repairs required here
Other major issues in emission failures are carbon deposits on the injection system, carburettor system; egr valve; inlet manifolds and it is here that dipetane comes into play as it will clean these deposits and it will allow the fuel to burn a lot cleaner.

As regards your "scientific quantity" the amount to be put in is gleaned from experience, nothing scientific; you leave that side of things up to the manufactures.
The amount stated by the manufacturers is a maintenance amount, to be used at every fill.
I would have to advise you not to put the whole bottle in on its own. It is not designed for that.
I do not know why some posters get so confrontational in a discussion

timmy4u2

Cosmo K wrote: »

Your are talking about a diesel, the OP's car is a petrol. Fuel cleaners in general, not just Dipetane, work to a certain degree when used to reduce diesel emissions.
In 99% of the cases however, they do nothing for petrol engines. I have seen this over and over again. Petrol car fails on emissions, customer comes back for a re-test after a week, nothing done to the engine, just a treatment with Dipetane-car fails again. Honestly, we see this nearly every flipping day. Especially 1.4 Volkswagen engines, they are real stinkers. Talk to a proper mechanic, and he will confirm that.


Cleveland hot pocket

I'm not sure what your qualifications are, but I can assure you, that every NCT tester is a qualified mechanic. That doesn't mean are always right, and never make mistakes-same as in every other profession, from guards to pilots-but to say that a lot of testers aren't even qualified is simply wrong.

Yes I gave the example of a turbo diesel as it was a very good example of what dipetane can do.
I have put it into a Ford Ka and it did a great job also.
In fact it has never failed me or any body I recommended it to.
And yes you are correct, in the beginning mechanical qualifications were not required but that is all changed for some time now.

timmy4u2

Cleveland Hot Pocket wrote: »

Are you agreeing or disagreeing with me? I think I'm missing something


I used to do this in reverse on an old diesel golf I had to clean it out.



Of course it works, you can see it working. Use it and do a pre, during, and after emissions test and you will see an increase when it works and then a decrease. I've seen it work on many cars so I know it works.

My qualifications are irrelevant to this issue.
I saw ads for NCT testers and contacted the company to ask what qualifications were required, only to be told that Leaving Cert was sufficient. Now this was back a couple of years to be fair so maybe the new crowd has a different policy.

The point I was making there is that it was not what somebody said, the figures were taken from the certificates before and after the introduction of dipetane.
I am on a small touch screen and puncutation may not be as it should at times as keyboard blocks script etc

jimgoose

timmy4u2 wrote: »

...I do not know why some posters get so confrontational in a discussion

Chimaera

Toyotafanboi wrote: »

i've also wondered what the "drive it hard on the way to the test center" does for a car.

Hard driving can blow out deposits, particularly in the exhaust and bring up the internal temperatures in the engine enough to burn off crap that might affect its performance. Though only doing it on the day of the test on a car that's usually babied around won't do much.

In general, fuel additives will work for engines that are just a bit under-utilised day to day and help clear out deposits of soot, etc. They won't help where there's an underlying mechanical/electrical fault. The OP's result is too far outside the limits for it to be fixable with additives or spirited driving.

Looking at OP's results, lambda is within normal limits but HC and CO are way off. This suggests that the combustion process is completing normally: lambda is a measure of how much oxygen is left over after combustion. The high CO and HC suggest that there's too much combustible material entering the engine: either it's overfuelling or burning oil. Further inspection by a mechanic is required.

Toyotafanboi

I would have thought there was no reason to quantify what those figures represented, after all we are talking about emissions.

in any preofession in life there is a need to state what your figures represent. otherwise there is a massive scope for error. were you referring to 7.2psi, 7.2mm, 7.2cc etc... its just a sign of intelligence/ common sense to state what you are referring to, particularly when making a point to a semi/ uneducated audience.

Who told you that a "heavy" emission falure is very obviously an engine failure that requires engine repairs.
If it was your mechanic I would change immediately.

a high emissions failure is almost certainly a failure of an engine component, not an "overall engine failure" as you have twisted my words to sound like.

Most emission failures are caused by external issues, Lambda and cat to name just two.
Neither of these issues require "engine repairs" just replacement of these external items.

thank you for re-enforcing my point above. i would classify component replacement after failure as repairs in/ on the engine.

A very bunged up air filter can have the same result. Again just a simple issue to replace the air filter. No "engine" repairs required here

i would certainly class that as maintenance/ repair work on the engine. unless its a magic air filter that replaces itself.

Other major issues in emission failures are carbon deposits on the injection system, carburettor system; egr valve; inlet manifolds and it is here that dipetane comes into play as it will clean these deposits and it will allow the fuel to burn a lot cleaner.

how does dipetane in the fuel system access the inlet manifold personally having seen very clogged carb's and very clogged egr's theres no substitute for removal and cleaning.

As regards your "scientific quantity" the amount to be put in is gleaned from experience, nothing scientific; you leave that side of things up to the manufactures.

so what you are saying is you feel that your experience of dipetane outweighs the manufacturers?

I do not know why some posters get so confrontational in a discussion

i'm not being confrontational. but as you say its a discussion forum and some things you said made me want to discuss them further.

timmy4u2

i'm not being confrontational. but as you say its a discussion forum and some things you said made me want to discuss them further.[/QUOTE]

You are right maybe I did not use the correct terminology. I should have used the one preferred by forum users, and now I am not going to feed either.

YbFocus

boldspirit wrote: »

I used a couple of quids worth of diesel in a full tank of petrol to give the engine a clean a day or 2 before the NCT worked just fine

Did you mean the other way around?

Petrol will clean a diesel engine in miniscule amounts, hardly the other way though?

jimgoose

YbFocus wrote: »

Did you mean the other way around?

Petrol will clean a diesel engine in miniscule amounts, hardly the other way though?

Modern diesel fuel contains a fair bit of detergent. But the best additive of all, if you must use one, is a tiny amount of marine two-stroke oil.

timmy4u2

jimgoose wrote: »

Modern diesel fuel contains a fair bit of detergent. But the best additive of all, if you must use one, is a tiny amount of marine two-stroke oil.

Yes you quite correct there. I use it on my Merc 220 CDI as these have a problem whereby they carbon up the EGR valve and the inlet ports and the butterflies on each cylinder.
It needs to be the non synthetic type.
http://www.brick-yard.co.uk/forum/adding-2-stroke-oil-to-diesel-tank-read-this_topic37935.html

jimgoose

timmy4u2 wrote: »

Yes you quite correct there. I use it on my Merc 220 CDI as these have a problem whereby they carbon up the EGR valve and the inlet ports and the butterflies on each cylinder.
It needs to be the non synthetic type.
http://www.brick-yard.co.uk/forum/adding-2-stroke-oil-to-diesel-tank-read-this_topic37935.html

According to the Yanks, NMMA (National Marine Manufacturers Association) standard TC-W3 is what you want. Apparently it's the additive package that does the trick, even in the recommended concentration of 1.9ml/l.

timmy4u2

jimgoose wrote: »

According to the Yanks, NMMA (National Marine Manufacturers Association) standard TC-W3 is what you want. Apparently it's the additive package that does the trick, even in the recommended concentration of 1.9ml/l.

What ever it is it works a treat. I found out about it on the Merc forum some time ago, pre arrival of dipetane
I had .94 on the emissions last NCT.

No Pants

Cleveland Hot Pocket wrote: »

I used to do this in reverse on an old diesel golf I had to clean it out.

That's impressive. What mileage did you do and at what speed?

Cleveland Hot Pocket

No Pants wrote: »

That's impressive. What mileage did you do and at what speed?

Hardy har har