VW Touareg 2.5 tdi 2006 - high emissions problem

[MARLBOROLITES]

Evening all, this was a summer impulse purchase and thus far has been a great but. But MoT time......

So an emissions fail.


Prior to the test I used Forte diesel treatment. The car had a full service with all filters replaced. She also had a pre MoT Italian tune.

Now there's no DPF on this model. I recently had a remap for better towing. After the MoT I discovered the EGR had been deleted. I'm running a Wynne's diesel treatment at the moment before I get a 2nd MoT. I've also ordered a 2nd hand EGR which I'll fit for the retest.

The guy that remapped her assures me it's not the remap. He has been remapping for years with no emission MoT fails. He said there'd be increased soot but no other adverse consequence. So I'm kinda pinning hopes on the re-installed EGR providing the response I need.

But I write letters for a living and would appreciate any thoughts.

TIA

[Adrian E]

Your major issue there is that the plate value appears to be 0.70, which is pretty low (it's the default value for post 1/1/2014 registrations). The 'default' value, in the absence of the 0.70 figure, which should be in a square box on the VIN plate, for your vehicle would be 3.0 - so borderline with what you've got on test.

Not sure refitting the EGR alone will solve the problem, if it's been mapped out, but might be a suitable workaround for the MOT. The risk if you leave it fitted without altering the map to include EGR parameters is that it'll clog up and not self-clean and give you running problems down the line.

It may need a more aggressive Italian tune up to remove as much soot from the exhaust system as possible before it's re-tested.

[Scrump]

It is a shame that your plate value is still readable. If it had become unreadable then the higher value would have been used as the pass level.

This is what I have been told but have not checked.

[Adrian E]

Scrump said:

It is a shame that your plate value is still readable. If it had become unreadable then the higher value would have been used as the pass level.

This is what I have been told but have not checked.

That would be true (at least if the VIN plate didn't have a value on it), but now the plate value is on the system for the vehicle I don't think that's an option, as it'll come up with the registration mark when tested in future IIRC

[MARLBOROLITES]

Thanks for this advice.

The car was remapped without awareness of the EGR delete. Might this be important and contribute to high reading?

The emissions at the previous MoT were well within tolerance which makes me wonder what's happened in the last 12 months?

Would a carbon clean be the way forward maybe? Coupled with EGR instal and more petrol treatment?

[Adrian E]

Did it pass last year with vales below 0.7? I can’t remember when the diesel emissions test moved to using plate values.....

[MARLBOROLITES]

I'm going to check when I get home.

I'm also tapping up knowledge on a Touareg forum. Turns out I'm missing the EGR valve itself, plus the EGR pipe to the cooler. A very thorough EGR delete if I ever saw one.

I have a carbon clean booked for next Tuesday. The car is in great condition for its age. She's worth a £ or 2 to get sorted.

[MARLBOROLITES]

A carbon clean solved the problem, my car passed the 2nd MoT with flying colours. Emissions were 0.5 average after 6 cycles. Car is noticeably smoother and running ever so well now. In fact she feels quite transformed. Best £99 I spent in a long while. The cost included a full diagnostic too.

[Sheepshanks]

Thanks for the update.

I was very worried about my Merc of similar age. It has a 0.9 in two squares on the VIN plate but it's not in the usual place and I'm not sure that relates to emissions - can't get a straight answer on that.

Last couple of times it's been tested at the default values, although the last one they used 1.5 instead of 3.0 so it only just passed. I put some black tape over the 0.9 for its last test and they used 3.