Metal plate in engine bay, or occasionally on B pillar.

Has VIN on it too. The smoke value is often in bottom right corner, and it should be in a rectangular box.

Stonekeeper posted an image of a MB data plate as an example - often located on drivers side B pillar.

This the badger?

 

 

Check for obvious boost leaks or have it smoke tested

 

My old octavia had high emissions and just passed a few years back. Mot tester noticed oil at intercooler pipe which on checking was partly blocked. It might be worth a check. I had a worn turbo and also one of the pipes wasn't sealing properly. There was a fair bit of oil and gunge in there.  I took it off and flushed it out and fitted a second hand turbo. Next time emissions were ok.

Alasdair

It might be worthwhile removing the throttle body and giving it a good cleaning and checking the pipes/hoses are not clogged up. I suspect that you perhaps might do a lot of short local trips which could result in the throttle body becoming clogged. Does the engine idle nice and smoothly, or is it a bit rough at all?  I had this issue on my last Superb and after cleaning it was like a new car and was also far more responsive and fun to drive.

15 minutes ago, Graham Butcher said:

It might be worthwhile removing the throttle body and giving it a good cleaning and checking the pipes/hoses are not clogged up. I suspect that you perhaps might do a lot of short local trips which could result in the throttle body becoming clogged. Does the engine idle nice and smoothly, or is it a bit rough at all?  I had this issue on my last Superb and after cleaning it was like a new car and was also far more responsive and fun to drive.

I mix short local trips with longer ones when I can to balance it out.   The idle is pretty smooth to be fair, not lumpy.  Just another source of my confusion!   A rough, smoking engine failing I could understand...

12 minutes ago, JamieH86 said:

I mix short local trips with longer ones when I can to balance it out.   The idle is pretty smooth to be fair, not lumpy.  Just another source of my confusion!   A rough, smoking engine failing I could understand...

I agree my octavia was absolutely disgusting. Full of black tar like gunge. The EGR valve was even worse. How it was operating I don't know. I think you can get a cleaner for in fuel but I just removed mine and soaked in kerosene and then cleaned. Made a big difference. Revs when idling were all over the place before cleaning plus got much better MPG afterwards.

4 hours ago, JamieH86 said:

I mix short local trips with longer ones when I can to balance it out.   The idle is pretty smooth to be fair, not lumpy.  Just another source of my confusion!   A rough, smoking engine failing I could understand...

Could still be worth trying, you seem to have had a good attempt at a doing a regeneration of the DPF with no joy, and it would be far cheaper of fitting a new DPF. Are you sure it even has a DPF fitted, how old is the car? 

14 minutes ago, Graham Butcher said:

Could still be worth trying, you seem to have had a good attempt at a doing a regeneration of the DPF with no joy, and it would be far cheaper of fitting a new DPF. Are you sure it even has a DPF fitted, how old is the car? 

No not got a DPF I believe.  2005.

On 30/11/2024 at 14:50, JamieH86 said:

Sorry, hate to miss info!  

 

It is 2005, don't think it has a DPF but I am not expert enough to know if "regen" specifically refers to DPFs or has a wider diesel meaning, too.

One of mine is an 08 1.9tdi with the pd BXE engine. It has a cat but no DPF something about the pd engine not liking them or so i've heard. It confused me as the DPF light came on on mine but didn't have one. Tracked that one down to the dash connector.

Thinking back if theres a bit of blackish soot on back of car and the airfilter is ok then maybe injectors(bad pattern) or intercooler full of oil. I once tried filling fuel filter with injector cleaner, It supposedly cleans injectors a lot better than an in tank additive. This was years ago on an old toyota people carrier as a last resort and it worked well but not sure if its a good or bad idea on a more modern skoda?? 

Have you had it read for fault codes? I(appologies if I missed it previously). 

Alasdair

 

8 minutes ago, Alasdair1 said:

Thinking back if theres a bit of blackish soot on back of car and the airfilter is ok then maybe injectors(bad pattern) or intercooler full of oil. I once tried filling fuel filter with injector cleaner, It supposedly cleans injectors a lot better than an in tank additive. This was years ago on an old toyota people carrier as a last resort and it worked well but not sure if its a good or bad idea on a more modern skoda?? 

Have you had it read for fault codes? I(appologies if I missed it previously). 

Alasdair

 

Should be getting it to a garage to check them tomorrow, haven't got a reader myself.

 

Come to think of it though, I had a thread here about a slightly worn intercooler hose (end result = patched it) where it hadn't been properly replaced and so was rubbing on the brake fluid business behind.  Anyway, there was a slight oily residue in the hose.  Not a lot but some.  Is that expected at all?

Any splits in inter cooler hoses will add to the smoke because warmer air will be getting in the pipe.

Yeah I'll take the hose off tomorrow and check there are no cracks or holes.

One other thought... let me know if this is wrong.

 

On the 'fast pass', which it passed in 2023, they pass it if the result is under 1.5 on the first rev attempt.

 

This year of course it wasn't so they did six full revs.

 

However... when taking it back to retest, oughtn't they to have started from scratch with a fast pass (which at 1.3/1.4, it would have passed)?

This time they used the plate figure, so 0.8 was what the car had to achieve.

3 minutes ago, Breezy_Pete said:

This time they used the plate figure, so 0.8 was what the car had to achieve.

Yeah true.  I didn't get a fast pass fail sheet from them, not sure if they tried it.

 

I didn't go to my usual place this year (ATS) as earlier in the year they did a few things with some other work that dented my confidence in them, but they do always start with a fast pass.

 

So tempted to book with them from scratch though.  But it could easily be 1.6 or something and then we're back to square one, plus I can't take it out for a spin now first!

 

Will report back findings from when any dirty bits have had a closer inspection, starting with the intercooler hose. 

On 30/11/2024 at 18:38, Breezy_Pete said:

Plate value is what they should use 'if it can be read'.

The wording in the test manual isn't wonderfully clear though, so the default limit is often mistakenly used. My A4 seems to have been tested to different limits almost in alternation.

Hmm, so the default value to be used if plated limit not readable - I wonder... 

On 30/11/2024 at 19:51, JamieH86 said:

This the badger?

 

 

 

Accidentally scrape the corner of the sticker so that the 0.8 is either removed or becomes illegible dependant on your relationship with the tester take it back to him/her or elsewhere for another MOT test, they would then have to use the higher default test limit from what others have said.

 

I dont know if that is what is supposed to happen as I have had but one car MOT tested in the UK (to be legal driving it to the ferry) in 20 years but logic tells me that accidental damage to the sticker is the smart thing to do.

My A4 has a plate figure of 0.7, currently easily legible...

Edited 6 December, 20241 yr by Breezy_Pete
Correction

Just now, Breezy_Pete said:

My A4 has a plate figure of 0.4, currently easily legible...

Quick trip to specsavers.

This is the exact wording of the test manual, for diesels of around this age.

I'm not surprised that some testers don't get it right if they skim read straight to "For vehicles first used before..."

 

 

Before the test, check the maximum smoke level limit for the vehicle and enter the required details into the diesel smoke meter.

The maximum smoke level limit will be the level displayed on the manufacturer’s plate; or where there is no manufacturer’s plate information:

For vehicles first used before 1 July 2008, the maximum level is:

• 2.5m-1 for a non-turbocharged engine
• 3.0m-1 for a turbocharged engine

For vehicles first used between 1 July 2008 and 31 December 2013 the maximum level is 1.5m-1 for all engines.

Source of the above, https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/8-nuisance#section-8-2-2

 

Unfortunately there's a sentence even further down the page than what I quoted, referring to retests after fails on emissions at plate figure. Retests must be done at same figure.

 

Has to be said though, there appears to be a lot of variability in how these tests are really done 'at the coal face'.

Edited 1 December, 20241 yr by Breezy_Pete

Yeah I was just going through that myself.

 

Well my two options seem to be check out where the issue could be, or deface the plates and go elsewhere.