Emmisions - 1.4 TDI - CT (MOT) Fail Yesterday

J

JWT

Member
I took my A2 for its CT yesterday which is only every 2 years in France. It would appear that the threshold for the emmision test has been changed since my last CT for this car.
I guess the question I am asking is what is the real life emmision level result that can be expected from the 1.4TDI 75 - whatever I do it may mean that the car will not pass - the accpeted level being less than or equal to 0.70m - the car achieved an average of 2.03 at the test.
Could anyone confirm the UK MOT test requirements ?
 
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I don't think the JWT has stated the mileage of his car. Unless it is luner (or intersteller) I suspect there is something amiss. Assuming the units are the same for UK and French tests ( 1/M), I have looked through past 20 MOT's on various old diesels I own (including A2's) and can report figures between 0.08 and 0.25. I am no mechanical genius but just make sure everything is correct.
The answer to JWT's question must surely be that yes the car is capable of passing a 0.7 test limit.
The most common cause of excess smoke is over fuelling, though this is the same as under airing. The first thing I would check/change is the air filter, though the ECU should compensate for this. Then there is the air mass meter. If this is telling the ECU it is getting more air than reality then smokey exhaust results. Possible boost hose leaks have the same effect.

Whilst there are potential expensive causes (turbo or faulty injector), most likely the fix could be very cheap, like a pipe popped off or a split rubber hose.

Trevor
 
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This is a smoke test? I suspect I know the reason for the last exceptional result 0.01 1/M for my car, it is usually in the range 0.3 to 0.6 1/M. I forgot to connect the EGR valve before the test. Would it make such a difference?
 
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I believe if the above fail to reduce it to under 0.7 then you should have it remaped by a rolling road specialist.
Most assume these are for more power but I do not see why you cannot stipulate emissions and economy to the tuner.
Emmissions and fuel economy will improve and power likely too.
 
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I can confirm that my own remap reduces the value to 0.1 and as remained at that on the last 5mot’s
The value in The uk is 3.0 for vehicles of the A2 age unless they see the plate value which is 0.7 but hidden under the carpet so unless you tell the mot man where it is the value checked against is 3.0

Cheers. Paul


Sent from my iPhone using Tapatalk
 
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The A2 went back in for its retest yesterday after having added the diesel and oil additive then taking a return trip to Bordeaux airport. It went into the test more than warm ! Results are that it still did not pass - best result 1.62 and the station apply the 0.70 value. Its dropped from the earlier result of 2.03 but thats no consolation unfortunatly - if it was in the UK it would pass no problem.
 
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Just an update - took the car back from France this week to WOM for full diagnostic check and a remap. End result is that the emission levels have dropped to a best 1.28 when tested in the UK.
I am now back in France and will get a retest here to see what the benefit of a 600 mile return run has done. I still need to get 0.70 otherwise its a no pass at the CT. Decision time !!!!!
 
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every year or two clean the MAF & MAP with say WD40 Specialist electrical contact cleaner......disconnecting( IMPORTANT ) the wiring from the MAF & MAP sensors to do & let dry for 15 mins before fitting back & reconnecting wiring.
Then use Wynns EGR 3 professional cleaner say 1/2 a spray can. ( Ive just ordered a can of Lucas EGR & Turbo cleaner to try).

Definitely check Air filter ( although I use a K&N filter)

Do NOT touch or prod sensors with anything !.....Just 10 quick shots of spray from every angle.
2021 MOT AT EXETER AUDI the opacity reading for emissions was 0.2
worth a try.
Cheers
Tones.
Just checked & had used Catalan that year before MOT. Previous was 0.61.
 

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Thanks for that information its appreciated - whilst at WOM last week the MAP & MAF Sensors were both replaced - is it Cataclean you are referring to Tones ??
 
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Hope that's helpful. I think we put it in with full tank just before a motorway run from Exeter to Reading & back a few days later when the MOT was due.
Some people say they put it in on the day of the MOT & drive the car down the motorway for a long run to the MOT so the engine is hot as well so book a time slot that they will do the MOT in the hour slot you book for the MOT.
You do feel the difference after as it pulls better through lower gears & with my EGR spray as well you can here the turbo sing.


Fingers crossed.
Tones
 

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Have you tried removing and cleaning out the inlet manifold? If it's never been done, it might (will) be full of glug!

RAB
 
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You could also try some injection cleaner. Also make sure that your air cleaner is in a clean state. If that doesn't get the desired result, maybe get the injectors tested; while they're out, renew the camshaft bearing shells - they will certainly need replacement!

RAB
 
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Is it right that the government can retrospectively change emissions levels? I'm all for cleaning up the atmosphere and lowering pollution, but it's not right to expect a 20 year old car to be able to pass modern standards - if they continue to pass the standards that were in place at the time they were first tested, that should be sufficient.

And don't get me started on the 'new cars are better for the environment' argument - it's been well proven that a well-maintained classic is just as 'good' for the environment as a brand new one (possibly even EVs). The best car for the environment is no car!
 
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