Mot question about emissions

[retromadness123]

Hello guys just a quick question that playing on my mind, I recently bought a 2010 octavia 1.9 tdi and when it's went in for a mot and failed on emissions, I then took in my 2001 w210 e220 cdi and that also failed on emissions, now these new rules on diesels, how harsh are they and I'm not sure but I'm sure more harsh rules on diesels are after 2005 with DPF fitted and also any tips to get the emissions low the mot guy says the octavia should be on 1 and the Merc should be on 2.3 don't know what he means by the numbers as the octavia is throwing a 4 and the Merc a 3 so any tip me on getting these down, I know the octavia is not retro material so do apologise but it's was a daily and like most modern cars it's useless , all help appreciated in advance

[mk2cossie]

What kind of state is the fuel filter on either vehicle?
The new testing standards are an for most of the diesel engines now, but most go through after an Italian tuneup and making sure the oil is hot enough for the test as well

The air filter can also cause headaches if it is clogged up as well

[retromadness123]

Both cars have been serviced and been on a long run before coming back to the station but the emissions still seem high, I know the Skoda is new so must be more strict, but the old Mercedes surely there must be lesser restrictions considering is 17 years old and the mot guy wants the emissions percentage to be on 0.8%, just so annoying how the government promoted diesels and now they doing us over by setting the bar so high, does this rule also apply to very old retro diesels as well as it just seems being a car enthusiast is going to be a thing of the past with all these things going on,

[welshpug]

its more a proper burn up you need to do than a long motorway cruise, they are quite efficient things thermally so high speed cruising doesnt heat them up.


as they are a fair way over the limits I would check the live data on diagnostic tool and compare against expected values

[Phil H]

I hope the Skoda hasn’t suffered from a previous owner being clever and giving it a DPF delete...

Italian tuneup for the win though - get it to temp then 5-10 minutes of foot to floor, needle to the red bit, action. My suspicion is you’ll see a real guy old cloud behind you for the first few minutes - repeat until you see no smoke signals.

[sausage]

i think failing on emissions will soon be par for the course on diesel MOTs. I love diesel so it sucks.

[ChasR]

Jul 11, 2018 18:09:58 GMT sausage said:

i think failing on emissions will soon be par for the course on diesel MOTs. I love diesel so it sucks.

It's not all bad news. It will get rid of some diesels that have long gone past some maintenance.

Yesterday I went past a completely clapped out MkV Fiesta TDCI. It was smoking from the rear like mental and even my 250D managed to overtake it! A remap's done that? No chance!

When my Alfa JTD was smoking (non-DPF) that was down to worn boost hoses; they weren't torn but they had gone weak and let air out, albeit slightly. This stopped completely with fresh Silicon hoses.

Emissions aren't the massive evil thing they are made out to be. I'm surprised I'm defending them but there are alot of knackered dervs out there; if people buy them for cost there is a much larger risk that they'll be run to a cost as well.

[sausage]

Agreed on the need for knackered diesels to be sorted or off the road, I just think this is the start of a series of ever increasingly stringent MOT standards that diesels will have to meet so am expecting it to just become an ordeal owning one in the coming years. I also assume this is the plan so we switch to electric, then when sufficient numbers have done so they too will be taxed to the hilt because of all the power stations / infrastructure needed.

[retromadness123]

Does the car need to have a dpf fitted for it to be tested to the manufacturers reading, as I been trolling the internet and only found a gov document stating about cars with dpf so in that case If I'm not wrong my w210 e220 on a W reg shouldn't have a dpf so the tester shouldn't be going by the manufacturers reading instead he should test it at 3.0% , any mot testers here can put my mind at ease guys

[mk2cossie]

It is tested to whatever the manufacturer's sticker says if it is after a set year.
And if there is no visible sticker or plate then it goes to default values based on year

Most of the dirty diseasals aren't a problem getting through. Its the ones with a bad remap, lack of decent runs or even just in a poor state service wise that are swines to get through the newer limits

[sausage]

Are decats a problem now or not?

[Phil H]

Jul 14, 2018 9:48:07 GMT sausage said:

Are decats a problem now or not?

Depends if it will still pass the emission test without one.

DPF delete now is though..

[mk2cossie]

Jul 14, 2018 9:48:07 GMT sausage said:

Are decats a problem now or not?

Yup. If any type of engine that originally had a catalytic convertor now has a de-cat it is a fail

And so are DPF that appear to have been tampered with, EGR system obviously defective or removed and the engine management light being on or not working at all

[duggers]

From the Gov.uk site for clarification

www.gov.uk/government/publications/mot-changes-from-may-2018-guidance-for-mot-testers/diesel-vehicle-emission-limits

www.mot-testing.service.gov.uk/documents/manuals/class3457/Section-8-Nuisance.html#section_8.2

[sausage]

Thanks,

First link Section 8.2.2 is about diesels, So if it had a cat and is missing it is fail. How does MOT tester know if it had one or not to make that decision? I have full stainless custom made exhaust system with no cat on a Y plate TDI.

[duggers]

Cat's were first seen around 1996 on Diesel cars but became a requirement for Euro3 vehicle emission standards in 2000.
So if the car is the requisite age, whether that's 2001MY on? , it should have a cat.
Not being a tester I assume they have a list or the requirement comes up on the computer when they enter the details but i'm sure someone with the accurate knowledge will come up.

[ChasR]

In short:

-They will look for a DPF. If it looks like it is missing it will be a fail. I.e a straight pipe where there used to be a DPF isn't going to cut it.
-There were going to be more stringent tests but I believe there has been an issue rolling this out. There may be a trickier test to catch out non-DPF owners but that's about it.

[mk2cossie]

Jul 17, 2018 6:21:11 GMT ChasR said:

In short:

-They will look for a DPF. If it looks like it is missing it will be a fail. I.e a straight pipe where there used to be a DPF isn't going to cut it.
-There were going to be more stringent tests but I believe there has been an issue rolling this out. There may be a trickier test to catch out non-DPF owners but that's about it.

There was something about if it chucks out a visible cloud of soot, but we have had several chuck out a cloud and pass the lower vehicle specific limits anyway

And the notes above are pretty much the same for catalytic convertors on diesels as well, but things like TD5 Discovery never had a cat on the earlier stuff, so it does become a headache trying to work out what did or didn't come equipped with either a cat or DPF