Help! Failed vehicle inspection emissions too high :(

skodaTdiJim911

New member
Joined
Dec 5, 2023
Location
Switzerland
TDI
Skoda Octavia 2 1.6 TDi
Hi everyone, I need your advice.
First off, I'm in Switzerland where emissions regs may be stricter (not sure).
Car = 2012 Skoda Octavia 4x4 1.6 TDi (common rail engine).
My car failed its inspection (called MFK here) because of emissions too high.
The rules are;
At idle, the particles per cm3 must be less than 100,000.
At 2000 rpm, the particles per cm3 must be less than 250,000.
At the first test my car had over 5,000,000 (5 million) particles per cm3. I took it to a garage (well recommended by a friend of mine, they speak English and I trust them) and they suggested first to try cleaning the DPF with an aerosol can, and a forced re-gen. They did that (for free), but on the next re-test it failed again with the same values (5 million).
So next I had the garage install a reconditioned DPF which I got from eBay. The recon DPF looked good - when looking inside everything was clean and you could see the welds on the case where they had opened it up and replaced the internals. The seller on eBay is a DPF specialist and has 94% positive feedback from 5900 sales... so seems trustworthy. It cost $300. It came just as the DPF with a flexi pipe. The old exhaust middle pipe had to be welded on to it.
Anyway I had a garage install it, which cost $900.
Today I got the car re-tested, and it failed again. The emissions have improved:
At idle = 300,000 particles per cm3 (max is 100,000).
At 2000 rpm = 400,000 particles per cm3 (max is 250,000).

So there is a dramatic improvement from the old DPF... but the tester said the values are "really high for a new DPF". Also I used to get a hesitation at < 2000 rpm in 4th gear when going up a slight hill. That is fixed now, so that's also an improvement.

So what do you think? Have I bought a defective DPF, or could there be something else wrong with the engine?
I'm $1200 into this so far... the car's worth about $3000 - $4000.
What should I do? Thanks in advance!
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
Were the basics checked?

- When was the air filter last replaced? Same for fuel filter?
- Could the injectors need cleaning?
- Fault code scan (maybe look for codes indicating a failing/sluggish MAF or other sensor)?
- Insufficient boost? Have you tried doing an "italian tuneup" (read: take it out on the highway and flog it hard)?
 

pedroYUL

Top Post Dawg
Joined
Sep 8, 2011
Location
MI, USA
TDI
2015 Passat CVCA; 2015 GSW CRUA; 2004 wagon BEW(brother)
We don't have that car/engine here, but was the new DPF adaptation done?
 

skodaTdiJim911

New member
Joined
Dec 5, 2023
Location
Switzerland
TDI
Skoda Octavia 2 1.6 TDi
Thanks for your responses.
I’ve only had the car for a year so I’m not sure on many of these. I can confirm the car had a new EGR before I bought it, and it had just passed the vehicle inspection. I also did an oil change myself with the correct VW oil (507) before the inspection.

Air / fuel filter state : not sure
Fault code scan: haven’t had time to check yet.
Insufficient boost: I’ve definitely given it an Italian tune up.. I know that the DPF works better when hot, so I drove on the highway at more than 3000 rpm for 10 minutes before the test. Power is good.

DPF adaptation: the mechanic confirmed to me he did this after the new (recon) DPF was fitted.

One thing I noticed - when I was driving home from the vehicle inspection yesterday, the car did a regen (the revs rose to 1000 rpm and the regen smell was there). That seems weird for a new (recon) DPF right?

The mechanic suspects there is something wrong with the recon DPF at the moment. The car is back with him now, he said he’s gonna try to test it himself.

thanks for your advice so far!
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
Air and fuel filters are relatively inexpensive and should both be fairly easy to replace.

Assuming this has a timing belt, is there any verifiable evidence of it having been changed? If not, consider dealing with that too - on most TDI engines, a failed timing belt/path component is a bad thing...
 

wayose

Member
Joined
Dec 8, 2024
Location
United States
TDI
just looking
Hi everyone, I need your advice.
First off, I'm in Switzerland where emissions regs may be stricter (not sure).
Car = 2012 Skoda Octavia 4x4 1.6 TDi (common rail engine).
My car failed its inspection (called MFK here) because of emissions too high.
The rules are;
At idle, the particles per cm3 must be less than 100,000.
At 2000 rpm, the particles per cm3 must be less than 250,000.
At the first test my car had over 5,000,000 (5 million) particles per cm3. I took it to a garage (well recommended by a friend of mine, they speak English and I trust them) and they suggested first to try cleaning the DPF with an aerosol can, and a forced re-gen. They did that (for free), but on the next re-test it failed again with the same values (5 million).
So next I had the garage install a reconditioned DPF which I got from eBay. The recon DPF looked good - when looking inside everything was clean and you could see the welds on the case where they had opened it up and replaced the internals. The seller on eBay is a DPF specialist and has 94% positive feedback from 5900 sales... so seems trustworthy. It cost $300. It came just as the DPF with a flexi pipe. The old exhaust middle pipe had to be welded on to it mot in peterborough.
Anyway I had a garage install it, which cost $900.
Today I got the car re-tested, and it failed again. The emissions have improved:
At idle = 300,000 particles per cm3 (max is 100,000).
At 2000 rpm = 400,000 particles per cm3 (max is 250,000).

So there is a dramatic improvement from the old DPF... but the tester said the values are "really high for a new DPF". Also I used to get a hesitation at < 2000 rpm in 4th gear when going up a slight hill. That is fixed now, so that's also an improvement.

So what do you think? Have I bought a defective DPF, or could there be something else wrong with the engine?
I'm $1200 into this so far... the car's worth about $3000 - $4000.
What should I do? Thanks in advance!
The car is now at around 51k KM and has had its 1st service with the SEAT dealer around 4 months ago (when hitting 40k). All works, no faults, but started getting the message: "Inspection Due!" every time the car starts. Whilst waiting for the answer from the dealer here in Catalonia I thought I ask here if anyone has any thoughts on this
 

pedroYUL

Top Post Dawg
Joined
Sep 8, 2011
Location
MI, USA
TDI
2015 Passat CVCA; 2015 GSW CRUA; 2004 wagon BEW(brother)
Inspection due is just a stupid reminder. Make a Google search on how to clear that...sometimes is press the trip reset button and hold while you click the switch to the first position.
 

ZippyNH

Veteran Member
Joined
Apr 22, 2015
Location
Southern NH
TDI
2015 JETTA TDI SE
One thought...
Typically most people know the dpf has gone bad by the fact a white glove will show soot at the tailpipe...
You had one go bad...fill the system with soot...
Now they stick a sample hose on your tailpipe and take a sample while it's running...
But the car hasn't been run for a few thousand plus miles to blow out the soot from the muffler and exhaust pipes?!
I would STRONGLY suggest that the soot being found in the tests are residual from the prior failure.
IMHO removing the exhaust and giving it a good cleaning before a retest would make sense
 
Top