Our car has failed its mot today on its emissions on the retest. It needed a few other bits doing but nothing major and my partner has changed the filter which reduced it considerably but it is still just over. Does anyone have any ideas on how we can improve it that bit more. I am so fustrated having to fork out another £50 quid for another test then they will probably find something else this time. :mad:

Our car has failed its mot today on its emissions on the retest. It needed a few other bits doing but nothing major and my partner has changed the filter which reduced it considerably but it is still just over. Does anyone have any ideas on how we can improve it that bit more. I am so fustrated having to fork out another £50 quid for another test then they will probably find something else this time. :mad:

If it's just over, one method is to book the next MOT and make sure the car gets a proper good thrashing before it goes in (aka Italian Tuneup) - You'll want it tested straight away.

It's worked for me in the past (especially with Fords)....

If it's just over, one method is to book the next MOT and make sure the car gets a proper good thrashing before it goes in (aka Italian Tuneup) - You'll want it tested straight away.

It's worked for me in the past (especially with Fords)....

Yes it is a ford. Only thing is we have to wait a week to get booked into that garage and I want my car now. Its so frustrating when everything else was fine and one drive round the block and it could have passed.

Thanks for the advice ming.

Put a pint of ATF in the tank that is half full and drive that off. Then fill with a good low smoke diesel - Shell is pretty good.

Once the engine is hot make sure that you run it up to the governer in all the gears (well tricky to do in fourth and top) - this will free off sticking rings and help shift any crud off the injectors.

Yes it is a ford. Only thing is we have to wait a week to get booked into that garage and I want my car now. Its so frustrating when everything else was fine and one drive round the block and it could have passed.

Thanks for the advice ming.

The bus garages add a small amount of methanol to the derv when an old bus fails a test due to heavy smoke. It is what they put in bio dieseI. I presume the same applies to cars. I am sure google will give the answer.

The bus garages add a small amount of methanol to the derv when an old bus fails a test due to heavy smoke. It is what they put in bio dieseI. I presume the same applies to cars. I am sure google will give the answer.

Funnily enough I suggested filling it up with a mix of biodiesel but my OH thought that was a stupid idea. I guess it would be if it breaks down. It seems to have coped well with him putting petrol in though. :loopy:

Should I take it back to the same garage or somewhere else. It will have to have a full re test now. It takes ages to get booked in there though.

If you've got a TDCi then don't put biodiesel in it! You could ruin the engine. Biodiesel is too viscous for modern diesels. It's fine for older diesels. Ford recommend a maximum of a 5% biodiesel blend, and on cars in warranty will invalidate the warranty if found to have been fueled incorrectly.

An italian tune-up is the best way to improve the emissions. Diesels actually work better when driven hard.

Erm....scrap it?

I thought a re-test was free.

I thought a re-test was free.

Yes it is we have done all the work it needed for the retest but the emissions were still just that little bit too high. So now it has to have a full retest.

If you've got a TDCi then don't put biodiesel in it! You could ruin the engine. Biodiesel is too viscous for modern diesels. It's fine for older diesels. Ford recommend a maximum of a 5% biodiesel blend, and on cars in warranty will invalidate the warranty if found to have been fueled incorrectly.

An italian tune-up is the best way to improve the emissions. Diesels actually work better when driven hard.

Cheers Ravenger it is an older Ford diesel and has a bosch pump so it should be ok for biodiesel.

My transit diesel failed on emissions.The garage changed the filters,put some kind of cleaner stuff in it and told me to thrash it on the way to the re-test.The guy testing it got a "just fail"again,ran it round the block and it passed.Not very scientific that,is it?

Our car has failed its mot today on its emissions on the retest. It needed a few other bits doing but nothing major and my partner has changed the filter which reduced it considerably but it is still just over. Does anyone have any ideas on how we can improve it that bit more. I am so fustrated having to fork out another £50 quid for another test then they will probably find something else this time. :mad:

When you say your partner had changed the filter? Which one? The quick fix & always a must with a diesel before the mot, is the AIR filter. If this is dirty or clogged it will fail. Other things to try are changing the FUEL filter. A dirty fuel filter will restrict the flow of the diesel & will alter the mix of fuel / air & alter the emmissions. Sometime fuel filters also have drain points on the bottom to remove any water that may have got in the fuel. The other thing to try is changing the ENGINE OIL & FILTER. Diesel engine oil differs from petrol engine oil in that it contains a detergent and gets contaminated a lot quicker than a petrol engine as burning diesel is a dirtier process as far as the engine is concerned, when compared to a petrol engine.

When you work out what the parts are going to cost,; i.e air filter, engine oil, oil filter & fuel filter you could probably get the lot for around £30-£35. It works out cheaper to fit them as a matter of course when the test is due rather than getting stung for the re-test fee at £50 a shot.

Let me know how you get on-good luck!

My old diesel van used to smoke like a chimney.
Before taking it for an MOT I'd take the diesel filter off and fill it up with neat additive.
Make sure there's not much diesel left in the fuel tank and tip the rest of the additive in that. Then take it straight to the MOT test.
It always passed easily.

Replace the air and oil filters, possibly also check / replace the glow plugs. More importantly, check the electrical wiring to the plugs and ensure the contacts are clean.

If the plugs aren't heating fully they won't burn the diesel. I cleaned mine on my previous 306 diesel and the smoke emitted from the exhaust dropped considerably.

The plugs will turn off after a few seconds of running though so that shouldn't be a problem. If the air filter is clear and the injectors not gummed or blocked it should be fine - if that doesnt solve the problem then you are looking at more serious remedial work being needed.