VW Polo High Emissions

Hunter321

Hi, I am having some problems getting my 06 Polo (1.2 Petrol) to pass the NCT. It has failed a number of times due to high CO. The latest readings are as follows:

Low Idle: CO = 0.02%, HC = 10ppm.
High Idle: CO = 0.51% (limit 0.2), HC = 20ppm
Lambda: 0.98

So far I have got a new Catalytic Converter installed, a full service, put a couple of bottles of Cat Cleaner in the tank. Diagnostics not showing any fault codes. Anyone got any suggestions. I'm thinking now it must be buring some oil. Thanks.

George Dalton

What kind of cat was fitted? From the readings it looks like a cat issue still. The HC figures do not suggest an oil burning issue.

Cleaning the throttle body, carrying out basic settings and clearing the adaptations in the engine ECU may just about scrape it through under the required CO %

Hunter321

Thanks for the suggestion George. I was told by the garage that the cat was a genuine VW part. It costs 500 euro and they said that was cheap. I would be a bit peed off if the cat was still a problem after paying so much. I don't think I have the know how to do the ECU work you suggested, think I might bring it to a VW garage at this stage.

Waterson

I wonder what sort of tests your garage did before replacing the most expensive part of your emissions system? Was there any improvement in the before and after CAT replacement emissions figures? What were the fuel trims like? True enough a CAT can get poisoned if, say, there was fuel pressure issues, but if the CAT was diagnosed as being the fault and there is stll an underlying rich running condition, the new part wont last too long either.

Hunter321

Waterson wrote: »

I wonder what sort of tests your garage did before replacing the most expensive part of your emissions system? QUOTE]

I wonder too Waterson. They said the cat was 'in bits', had broken up. I didn't see it so have to take their word for that. I just checked the original NCT and the CO has improved since the new cat was installed, was 1ppm, now 0.5ppm. So obviously an improvement, but still some other issue. Think I might drop it into a VW dealer today as I wouldn't have the diagnostic equipment needed.

John T Carroll

Hunter321 wrote: »

Hi, I am having some problems getting my 06 Polo (1.2 Petrol) to pass the NCT. It has failed a number of times due to high CO. The latest readings are as follows:

Low Idle: CO = 0.02%, HC = 10ppm.
High Idle: CO = 0.51% (limit 0.2), HC = 20ppm
Lambda: 0.98

So far I have got a new Catalytic Converter installed, a full service, put a couple of bottles of Cat Cleaner in the tank. Diagnostics not showing any fault codes. Anyone got any suggestions. I'm thinking now it must be buring some oil. Thanks.

It should go without saying but the "full service" should have included spark plug renewal, also, as stated in another post, the throttle body should be cleaned.

dieselbug

Hunter321 wrote: »

Waterson wrote: »

I wonder what sort of tests your garage did before replacing the most expensive part of your emissions system? QUOTE]

I wonder too Waterson. They said the cat was 'in bits', had broken up. I didn't see it so have to take their word for that. I just checked the original NCT and the CO has improved since the new cat was installed, was 1ppm, now 0.5ppm. So obviously an improvement, but still some other issue. Think I might drop it into a VW dealer today as I wouldn't have the diagnostic equipment needed.

Whatever the problem is that caused the original cat to break up still exists.
The emissions are lower because the new cat is working hard to bring them down, not for long though. If you dont get it sorted the new cat will also break up as it being overworked.
A sample of the exhaust pre the cat would show the true story. You need to take action on it asap if you dont want to see your e500 go up in smoke.

John T Carroll

dieselbug wrote: »

Hunter321 wrote: »

Whatever the problem is that caused the original cat to break up still exists.
The emissions are lower because the new cat is working hard to bring them down, not for long though. If you dont get it sorted the new cat will also break up as it being overworked.
A sample of the exhaust pre the cat would show the true story. You need to take action on it asap if you dont want to see your e500 go up in smoke.

Should have mentioned above that the cam sensor should also be checked, this will show up in any reputable scan. It went in my wife's new 2005 Polo after only 1 month, the exhaust manifold was white hot and there was a terrible smell from the engine area, I assume that the ignition timing was only being done in a crude fashion by the crank sensor, I wasn,t around at the time but when my wife mentioned the white hot exhaust and the terrible smell, the main dealer replaced the Cat as well, dont know if it actually needed it but it may have shown up on their diagnostics as these Polos have two Lambda sensors, the second one shows up the efficiency of the Cat. I'm not sure if the emission warning light was illuminating occasionally as well.

Of course there may be some far more mundane reasons for the Cat breakup, driving into a flood wouldnt do it any good.

dieselbug

John T Carroll wrote: »

dieselbug wrote: »

Should have mentioned above that the cam sensor should also be checked, this will show up in any reputable scan. It went in my wife's new 2005 Polo after only 1 month, the exhaust manifold was white hot and there was a terrible smell from the engine area, I assume that the ignition timing was only being done in a crude fashion by the crank sensor, I wasn,t around at the time but when my wife mentioned the white hot exhaust and the terrible smell, the main dealer replaced the Cat as well, dont know if it actually needed it but it may have shown up on their diagnostics as these Polos have two Lambda sensors, the second one shows up the efficiency of the Cat. I'm not sure if the emission warning light was illuminating occasionally as well.

Of course there may be some far more mundane reasons for the Cat breakup, driving into a flood wouldnt do it any good.

When the cat breaks up it may and often does block up the exhaust. This will cause the manifold to glow hot.

Hunter321

Thanks for all the replies. I brought it to a dealer and just got a call from they to say they have diagnosed it as a faulty fuel injector and coil. another 600 euros !!!! Does that sound expensive.

Waterson

The likelihood of an injector and a coil failing together is slim. For there not to have at least been a lean mixture fault code logged...very slim. How was the car running, specifically when accelerating? Misfiring or power loss issues? Be wary of garages who think that fixing cylinder specific misfires by throwing components at the problem (at your expense) is the way forward. It doesnt sound an outrgaeous price IF both coil and injector have failed. I would definitely be looking for a guarantee of workmanship however before you part with your money, i.e. no fix no fee.

John T Carroll

Waterson wrote: »

The likelihood of an injector and a coil failing together is slim. For there not to have at least been a lean mixture fault code logged...very slim. How was the car running, specifically when accelerating? Misfiring or power loss issues? Be wary of garages who think that fixing cylinder specific misfires by throwing components at the problem (at your expense) is the way forward. It doesnt sound an outrgaeous price IF both coil and injector have failed. I would definitely be looking for a guarantee of workmanship however before you part with your money, i.e. no fix no fee.

Surely they would have cleared the fault codes and swapped the suspect coil with one of the other cylinders, then if their original diagnosis was correct you would end up with fault codes on two cylinders, if only the misfire "followed" the suspect coil then its only the coil that needs replacement, it is recommended that all three are replaced together, I replaced them on the 2005 Polo in 2011 and 51,700 Kms at a cost of around €135, as far as I recall.

Waterson

We wouldnt know what diagnostic procedure has been followed, sure swapping coils and folloiwng misfire counters is a fine way to do it; coils do fail on these engines no doubt, but an injector and a coil failing together? Smells like a parts changing procedure to me anyway. So really if thats all they have done, the E600 even with genuine parts and labour is a p*** take. They'd at least want to provide a clear emissions test result to back up the fix.

Hunter321

Had a chat with them today. One of the spark plugs was badly contaminated even though these were replaced only a couple of weeks back. Although there was no engine management light, diagnostics showed a rich burn. They also did a compression test which was fine and an emission test which matched the NCT. They said the faulty injector damaged the coil, although I'm not too sure how they know the coil is faulty. Cost breakdown is E175 for injector, E55 for coil and three hours labour (fitting, repeat test, etc.). Just to clarify that this was not the original garage that replaced the cat. Is it possible that an injector issue could have damaged the cat and would I have had to replace it anyway. Its working out as a expensive one for me, but hopefully will be sorted out now. Talk of penalty points for no NCT from next week.

John T Carroll

Hunter321 wrote: »

Had a chat with them today. One of the spark plugs was badly contaminated even though these were replaced only a couple of weeks back. Although there was no engine management light, diagnostics showed a rich burn. They also did a compression test which was fine and an emission test which matched the NCT. They said the faulty injector damaged the coil, although I'm not too sure how they know the coil is faulty. Cost breakdown is E175 for injector, E55 for coil and three hours labour (fitting, repeat test, etc.). Just to clarify that this was not the original garage that replaced the cat. Is it possible that an injector issue could have damaged the cat and would I have had to replace it anyway. Its working out as a expensive one for me, but hopefully will be sorted out now. Talk of penalty points for no NCT from next week.

Its strange that a faulty fuel injector would damage an ignition coil. The cat would certainly be damaged/destroyed by a leaking fuel injector OR a misfiring ignition coil, the most puzzling thing is why, seemingly everything was fine, starting, idling, driving etc until the NCT test and the fact that there were no fault codes or that the emissions warning light did not illuminate. In my experience, when the cat is on its way out under normal circumstances, fault code P0420 has been stored with the emissions warning light "up". I even saw this on an 2001 Golf recently and renewing the Cat solved the problem.
At the same time, even if the fuel injector doesn't need replacing, I suppose if the whole problem is sorted out then fair enough.

dieselbug

Hunter321 wrote: »

Had a chat with them today. One of the spark plugs was badly contaminated even though these were replaced only a couple of weeks back. Although there was no engine management light, diagnostics showed a rich burn. They also did a compression test which was fine and an emission test which matched the NCT. They said the faulty injector damaged the coil, although I'm not too sure how they know the coil is faulty. Cost breakdown is E175 for injector, E55 for coil and three hours labour (fitting, repeat test, etc.). Just to clarify that this was not the original garage that replaced the cat. Is it possible that an injector issue could have damaged the cat and would I have had to replace it anyway. Its working out as a expensive one for me, but hopefully will be sorted out now. Talk of penalty points for no NCT from next week.

Do you know what the engine code is and was there any fault codes stored, especially misfire ones..
Did they give you the results of the compression test?
If there was a misfire code the ecu would shut off the injector on that cylinder to protect the cat, but if the injector was leaking .....

Some of these 3cyl polo's had known issues with timing chains and compression related misfires. The main dealer would be well aware of these.

Hunter321

dieselbug wrote: »

Do you know what the engine code is and was there any fault codes stored, especially misfire ones..
Did they give you the results of the compression test?
If there was a misfire code the ecu would shut off the injector on that cylinder to protect the cat, but if the injector was leaking .....

Some of these 3cyl polo's had known issues with timing chains and compression related misfires. The main dealer would be well aware of these.

They didn't tell me what the engine code, but did mention the fuel ratio being 'rich'. Got an NCT appointment for tonight, so fingers crossed. A lot of good information around this forum, in future i'll come here earlier, might save a few quid.

John T Carroll

Hunter321 wrote: »

They didn't tell me what the engine code, but did mention the fuel ratio being 'rich'. Got an NCT appointment for tonight, so fingers crossed. A lot of good information around this forum, in future i'll come here earlier, might save a few quid.

The best of luck tonight, it would be very interesting to see what the codes were, you may be "entitled" to them since you (rightly so) paid for the diagnostics but because they were part of the "fix" you may not be. The garage may be of the view that we "fixed" your car and the diagnostics are solely our business.

Hunter321

Just back from NCT, passed with flying colours, CO practically zero. So it looks like it was an injector and/or coil issue, probably never know which. One thought in my mind is would it have passed with the old cat had it been diagnosed correctly at the start, maybe not. Not much point worrying about it now. It was a costly one, but at least I dont have to worry about it again for anoither two years.

discodavie

Hunter321 wrote: »

Just back from NCT, passed with flying colours, CO practically zero. So it looks like it was an injector and/or coil issue, probably never know which. One thought in my mind is would it have passed with the old cat had it been diagnosed correctly at the start, maybe not. Not much point worrying about it now. It was a costly one, but at least I dont have to worry about it again for anoither two years.

Been following the thread. Congrats and delighted for you.

greasepalm

lucky you i was waiting for the bit with worn valve guides causing car to run rough on tick over,bloody expensive are those 3 cylinder engines.

Hunter321

Thanks for that. I will be a lot wiser in future when having problems with my car. Will not just accept part replacement and hope for the best. Problem is when you need your car for work you just want it fixed ASAP.

On a seperate note I wonder if the guards will enforced the new 3 point for no NCT. You come out of the NCT with a minor problem and get 3 points at the checkpoint down the road. Then you wait two weeks for a recheck and get another few points. Seems a bit unfair.

braddun

disconnect the battery to reset the computer for about 30 minutes

add bottle stp and drive around then add another before test

High CO means your car is running rich, more fuel than air. High HC means it's lean, more air than fuel. If your car was cold and not allowed to warm up to normal operating temp. before taking the test it would explain the rich reading. Cars always run richer cold, plus, if your air filter is plugged it's not getting enough air. An oil and filter would never hurt to have changed anyway and could contribute to rich readings if the oil has been contaminated with blow-by fuel. Some fuel does get by the rings and is pulled back into the intake through the PVC. The longer between oil changes the more diluted the oil the higher the CO to an extent. I'd get the oil and filter changed plus change the PVC valve and air filter. Then take it for a good long ride and retest it.

Hunter321

braddun wrote: »

disconnect the battery to reset the computer for about 30 minutes

add bottle stp and drive around then add another before test

High CO means your car is running rich, more fuel than air. High HC means it's lean, more air than fuel. If your car was cold and not allowed to warm up to normal operating temp. before taking the test it would explain the rich reading. Cars always run richer cold, plus, if your air filter is plugged it's not getting enough air. An oil and filter would never hurt to have changed anyway and could contribute to rich readings if the oil has been contaminated with blow-by fuel. Some fuel does get by the rings and is pulled back into the intake through the PVC. The longer between oil changes the more diluted the oil the higher the CO to an extent. I'd get the oil and filter changed plus change the PVC valve and air filter. Then take it for a good long ride and retest it.

Thanks for the advice, but maybe you haven't followed the full thread

John T Carroll

Hunter321 wrote: »

Thanks for that. I will be a lot wiser in future when having problems with my car. Will not just accept part replacement and hope for the best. Problem is when you need your car for work you just want it fixed ASAP.

On a seperate note I wonder if the guards will enforced the new 3 point for no NCT. You come out of the NCT with a minor problem and get 3 points at the checkpoint down the road. Then you wait two weeks for a recheck and get another few points. Seems a bit unfair.

You can get it done 90 days before the due date and the certificate will issue from the due date once you pass the NCT, you can also get it done more than 90 days before the due date but the cert will issue from the pass date.

John T Carroll

John T Carroll wrote: »

You can get it done 90 days before the due date and the certificate will issue from the due date once you pass the NCT, you can also get it done more than 90 days before the due date but the cert will issue from the pass date.

Here it is from the NCT.
http://www.ncts.ie/bookings.html