MOT Failure Emissions Brakes and Lights with solutions

[Captdave]

Hi Guys,

Just put my car through its ITV or MOT to you boys and it failed for Lights, emissions and brakes its a 2004 A6C5 Avant quattro 2.5 tdi with 206,000 kms.

Lets deal with the emissions first I had changed the EGR valve a few months ago but I noticed my engine light had come back on recently.  I managed to turn it off with an OBD reader(fault being insufficient exhaust gas recirculation) but it failed the emissions test anyway so I thought I had better have a look.  It transpires that the valve was opening OK but actually lifting up the valve seat at the same time so no exhaust gas was able to circulate hence the yellow light on again.  I fixed the valve by securing the valve seat so it could not move (drilled and tapped with grub screw) and bingo after reassembly and running for 10 mins or so out went the engine warning light, great, so back to the local testing station where the car failed again for emissions (to much smoke) which I have to say was a little disappointing.  So I had a look around on the internet for anti smoke treatments etc but while looking I found a brilliant article on this very topic by Highmotor.  In the article he suggests that if your car only does short trips (like mine) it can lead to a build up of soot in the exhaust sufficient to fail the test and his solution is TO RUN THE CAR FOR ABOUT 30 KMS IN A LOW GEAR AT MAXIMUM REVS ON THE MOTORWAY TO BLOW OUT ALL THE SOOT.  I thought I would give this a try and so this time I went to a testing station about 40 kms up the road in 3rd gear at 4000 rpm and the car passed no problem at all. So before you try any other cures and treatments give that a go it might be obvious to some people but it was not to me I was thinking injector change which is very expensive.

My car also failed for brakes so I had a look at them, the rear the pads and discs were very very worn so I changed them and back I went to the ITV station where it failed again for brakes being inefficient. I knew the brakes were fine (being a retired mechanic) handbrake was very effective and while driving the car stopped perfectly so I had a cunning plan.  A few years ago my motorhome would not pass the brake test whatever I did and I did a lot over several months until finally one of the technicians at the testing station sort of implied the motorhome might need more weight in it to pass.  So next time I went for the test I loaded the camper with my motorbike on the back and my pal sitting in the toilet and it passed easily.  There never was anything wrong with the brakes just the way their stupid rolling road works.  So next time I went to the testing station with the Audi I put about 5 jerry cans filled with water and two large gas bottles in the back and hey presto car passed with flying colours along with the emissions.

The lights were an easy fix if a bit tedious. My car had a plastic sort of film covering the headlights and this had started to degenerate and peel off in places. The cure was to attack it with plastic scrappers and varying grades of sand paper (400 to 2000) until all the film was removed and then polish them with a machine so they came up great and passed the test easily.

 

So I hope this helps some of you pass your MOT or ITV test its good to pass on some useful tips to like minded souls I think anyway.

 

Bye for now

 

Captdave

 

[cliffcoggin]

Top marks for ingenuity. I have to suspect the brake test at your testing station if it can not cope with different vehicle weights. Would it fail the brakes on a really light car I wonder?

As for the EGR, without it for so long soot is bound to accumulate in the exhaust. The better solution is not to blow it out at high revs, but to burn it out by initiating high temperature regeneration, which the ECU normally takes care of but which I believe can also be done from a decent code reader.