Causes of Diesel MoT Emissions Failure

[cancunia]

I was looking at an MoT history earlier for a Toyota Hiace. It's twice failed on emissions, then passed with no increase in mileage. I looked at another which had exactly the same problem.

I'm wondering how things were fixed without any miles, if it was once then perhaps something was replaced, but twice makes me wonder if it was snake oil, or maybe they simply hadn't warmed the engine up before testing.

[brodfather11]

Was the date the same ? . There may be a well known cause and simple cure that enables them to pass the same day.
That could be done without mileage being clocked up.

[cancunia]

Was the date the same ? . There may be a well known cause and simple cure that enables them to pass the same day.
That could be done without mileage being clocked up.

That's what I was wondering. Pass was same day / next day / day after next

[ffrenchie]

They take it outside and sit with their foot on the accelerator for 5 minutes to get it hot then put it through again usually.

[cancunia]

They take it outside and sit with their foot on the accelerator for 5 minutes to get it hot then put it through again usually.

Ah, Italian Tune Up! I did wonder. I came across another this morning with the same history. Fail, then Pass same day, same mileage.

[polar]

Millers - tip the full bottle in and then go and give it a good thrashing in 3rd gear = job done

[El Berlingo]

Hi,

My Berlingo failed its ITV ( Spanish MOT ) through emissions failure.
Bought some additive to clean Diesel engines ( Redex, 2CV, Wynns, et al) and gave it large revs down the Autopista . Straight back to test station, passed with flying colours. I suppose this is a ‘Spanish Tune up’!

El Berlingo

[John B]

Before I bought my Berlingo I had a Ford Fiesta 1.8 diesel van, which failed its test on emissions. My local garage put a gallon of petrol in the fuel tank, then told me to give it a good run giving plenty of revs for half an hour. It ran fine and passed the retest.

John

[ron]

Before I bought my Berlingo I had a Ford Fiesta 1.8 diesel van, which failed its test on emissions. My local garage put a gallon of petrol in the fuel tank, then told me to give it a good run giving plenty of revs for half an hour. It ran fine and passed the retest.

John

Don't do this with a common rail.(HDi) unless you add plenty of 2 stroke oil.Even then I would be wary.
I usually fill my tank a couple of weeks before & double dose  with Millers.It's worked OK so far.

[cancunia]

Yep, I'd be wary of putting petrol into a modern diesel. I've heard about putting a high dose of Millers or similar into the fuel filter bowl, easy enough to do on the 2.0 Berlingo.