Hi, my 2014 1.5TDCI Fiesta recently failed MOT for:

Repair immediately (major defects):

• Exhaust emissions exceed manufacturer's specified limit 0.54 (8.2.2.2 (a))
• Exhaust on a vehicle fitted with a diesel particulate filter emits visible smoke of any colour (8.2.2.2 (d))

Monitor and repair if necessary (advisories):

• Exhaust emits excessive smoke or vapour but not likely to obscure the vision of other road users (8.2.2.2 (c))

 

Would the problem most likely be the diesel particulate filter? I mostly drive it for short journeys and have read that driving it harder could remove soot buildup but I'm not sure, hence I'm asking. I don't think its the engine since I haven't seen anything out of the ordinary, oil is topped up and was serviced around 6 months ago.

I also wanted to ask if this would be covered under warranty from the second hand dealer I bought it from, it is still under 6 months but they're claiming that this 6 month warranty only applies to cars 5 years and under.

 

Thanks, Chris

This is purely a driving style issue,  short journeys dont heat the DPF so they dont filter the exhaust and clog with carbon(completely burnt diesel) so you need to do a dpf regen, other members will be able to help.

I did do some driving at around 3-4k RPM on the dual carriageway, but wasn't sure if it was doing anything since I didn't see a DPF light on the dash (if ford even has one), also not sure on how long to do it for. But anyways, my MOT is expired now so I can't drive it on the road unless I take a really long way to the garage.

Call the MOT centre and ask for advice, theyll maybe use the trade plates to give the car a clear out, does the car use the AdBlu stuff?

The MOT centre doesn't know whats wrong with it, they suggested a full service, but then said they're not sure if it will fix the problem. They said go to a diesel specialist or a ford dealer. I think fuel additives can unclog the filter too but not sure, I've never tried it before.

there won't be any light on dashboard to tell you it's doing a regen. A lot of people say they can feel a difference in the engine note/roughness when it's doing it. I can not tell. The only sign that mine is doing a regen (at least I think it's a sign of regen) is when I pull up at traffic lights etc I can hear the radiator fan going flat out even though temp guage is normal and the fuel consumption is showing 2 litres per hr instead of the normal 1.  (on my car the mpg reading changes to litres per hr when the car is not moving).

How far above the limit was emissions, as it failed I assume they gave you the printout. 

What's the mileage on this car?  does checking MOT history on Govt website look like the mileage might be genuine? (I know it could still have been clocked in first three years).

If there was a problem with dpf I would have thought the car would have gone into limp mode with EML on. If a dpf is clogged I don't think it usually starts letting soot through, I think the back pressure is picked up by the sensors and the car goes into limp mode with EML on.

So might it have had the dpf gutted before you got it due to previous problems with the DPF? It does not sound likely for a car of that age, but if a previous owner was always doing short journeys they might have had previous dpf clogging problems and had it gutted (against the rules)

 

I believe if you put a good ELM327 code reader on the OBD port (cost less than 20 quid) with Forscan software (free for Windows, about 6 quid for Android/iphone) it can tell you how many miles it has done since the last regen. I believe it can also be used to force it to regen - I have not tried it, I am going by what I recall reading on these forums.

I see your MOT has expired, what I would be inclined to do is a 60 mile round trip using 4th gear and 70MPH for the majority of the journey. This will heat the exhaust system and give it a good blast.

 

It's got around 62000 miles, not sure how long these dpf last, but something has happened in the last year since MOT was fine a year ago, with no advisories.

Was it tested hot or did they just drag it in cold and stick it on the smoke machine?

I'd suggest there's nothing actually wrong, it just needs a clear out or at least a warm up.  You'll know if the DPF is trying to regen as the fan will be running at full speed sounding like a jet engine...

Best option is to get Forscan on it as Isetta says.  But if that's not an option, just give it a hammering on the way to the test centre and make sure they take it immediately instead of parking it up for a while.

Never failed CATACLEAN put that in and drive around if you can for approx 30 mins then take it back for retake ,it will pass.also please use a DPF cleaner additive once a month or stick to Cataclean ,it will help keep it clean.

 

https://www.eurocarparts.com/p/cataclean-diesel-dpf-cleaner-450ml-542771700?type=shopping&gclid=CjwKCAiA98TxBRBtEiwAVRLqu_fiSON7nO2t2pbGAW1mOtriw7WTy8fPsZsGgMTF8nMmrUlfdI41ORoCzxEQAvD_BwE

The test centre is around 5 mins from my house so the engine was most likely cold when they tested it, that was bad on my part, I should have drove it around before going there but was thinking nothing would go wrong.

I might try out that cataclean stuff, they do sell it in halfords so might go tomorrow and pick some up.

13 minutes ago, Chris8888 said:

The test centre is around 5 mins from my house so the engine was most likely cold when they tested it, that was bad on my part, I should have drove it around before going there but was thinking nothing would go wrong.

That could account for the failure. What were the tested figures and did they say what colour the smoke was?

I'm intrigued about the smoke, It must have been bad for a visible smoke failure as well and one reason might be that it was doing a Regeneration while it was being tested. If it was it almost certainly have failed.

The rules changed in 2018 but I would have expected a reasonable tester to have taken it for a run and immediate emissions retest of the emissions it circumstances like that.

The MOT testers are supposed to run it up to temperature before testing the emissions. I think they check oil temp and it has to be at a certain level before they start reading emission, so I wouldn’t have thought the issue would have been cold engine. 
If you can get it out for a long run and stretch it’s legs, that might do the trick. Bottle of redex as well potentially, a can of EGR cleaner...and take the long way to the MOT centre for your retest. 

Average reading was 4.31 1/m, manufacture limit is 0.54, so quite high over. I didn't ask about the colour of smoke, but when looking for myself, it isn't dark colour smoke, always light colour, even when I take it up to high RPMs.

17 minutes ago, Tizer said:

one reason might be that it was doing a Regeneration while it was being tested

If it was doing this, then that's just bad luck.

20 minutes ago, Chris8888 said:

Average reading was 4.31 1/m, manufacture limit is 0.54, so quite high over. I didn't ask about the colour of smoke, but when looking for myself, it isn't dark colour smoke, always light colour, even when I take it up to high RPMs.

If it was doing this, then that's just bad luck.

FK me that is quite a bit over. I had a Corsa once with a seized EGR valve and managed to squeak it through at 0.54 on the button....

What you mentioned earlier about the garage suggesting a full service, without knowing what the problem was or whether it would solve it, says to me that the garage either don’t know what they’re doing, or they are bullsh*tters. Either way, I would take it elsewhere for it’s MOT. 

I also don't think that changing the Oil and Air Filter will bring it down from 4.3.

If the white smoke is not just condensation because the engine was too cold and it was not doing a regeneration then it is indicative of a more serious problem.

A steady run down the Motorway in fourth gear should trigger a Regeneration if one is required and remove that from the possible causes.

I booked it in at a ford dealer for a diagnostics test this Friday to see what the actual fault is.

Update, Ford did their own emissions test and it came back negative, I took it for a retest and it also came back negative. Absolutely nothing was done to the car, they didn't even charge me for the diagnostics test because they couldn't find any faults. I still don't know why it failed the first MOT.

For people here looking for an explanation on why their car failed for emissions, sorry you couldn't find the answer here. My advice would be just to make sure the engines hot when you arrive at the test centre.

Thanks for updating. I reckon the testers in the first MOT made a mistake of some kind. 

That is good news. I'm still sure that the car either was doing a Regeneration at the time it was being tested or it was too cold, either way a Boy Scout would have been able to work that out at the time never mind a Mechanic.

Prior to my current car I have had Diesel cars for years and the only time one of them failed an emissions test was when the testing station could not test it at the agreed time and I left the car with them. Needless to say when they tested it a few hours later it failed. They did the correct thing though and took it for a run and it passed no problem when hot.

For information I'm sure I have read in past DVLA advice that a car should be taken for a 5 mile run prior to being presented and you should not rely on warming  it up by allowing it to Idle. The Oil temperature should also be taken  but this is more to prevent engine damage and I'm sure the minimum temperature is only 60 degrees.