Diesel emiissions - failed MOT

Assuming it's the soot test, you can replace the air filter, run this tank low of fuel, use plenty of injector cleaner combined with some Italian tuning *then* put in a substancial amount of a GTL diesel (BP Ultimate Diesel, Shell V-Power Diesel, Total Excellium Diesel) - ignoring the higher price - and resubmit the test.

All of the above assuming the engine wasn't too much higher than the limit. If the donk produces a smokescreen that a tramp steamer would be proud of, ignore the above... :-)

Thanks for that - I'll give it a try.

I was sure I read someone on here had used a tankful of bio-diesel or cooking oil to get a vehicle to PASS the emissions test. I guess I misunderstood.

My dads' Astra diesel failed last week on emissions - the garage itself tossed him a bottle of stuff, but rather than using the measured amount per the instructions, told him to shove the whole lot in.

It used to be smoky on acceleration, but whatever it was cleaned it up noticeably apparently.

It was re-tested today, and passed quite happily.

Run the tank down a bit then add a bottle of "diesel magic", go for a ten mile drive and rev the hell out of it in third gear, keep dropping down to a crawl then rev it again. It should clear most of the crap and result in a pass.

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That's the most important bit, plenty of full throttle acceleration through the gears right up to the rev limiter.

The ''smoke'' the makes the MOT failure isn't smoke as such, it's just carbon on the inside of the exhaust that's built up over the year due to gentle driving - it needs to be dislodged. 9 times out of 10 you don't need any additives, just a good blast prior to arriving at the MOT station.

Julian.

Yup, my friend did exactly that with his old Land Rover. Worked a treat, but the vehicle was old enough only to have to pass the visual test for excessive smoke, rather than a proper emissions test. Probably stating the obvious, but it needs to be _unused_ cooking oil - home-filtered chip-shop waste is unlikely to improve anything.

Thanks all, for your suggestions. I'll put some BP diesel in and do my impression of a boy racer. Need to find a baseball cap and some blue LEDs.

If what you say is true then it makes me wonder what the point of these tests is.

A good blast can be literally the thing. A couple of years ago the local kids found it extremely funny to shove a firework up the exhaust of my pick-up. I heard the bang, it was late October, so we were used to hearing them. Next morning I found a big black patch on the concrete below the tail pipe where the blast had loosened it from inside the rear box, and when I drove off, f*ck me I was lucky not to be arrested I should think.

Passed the test a couple of days later though. :-))

Steve

Once you've passed you won't be smoking anymore.

It's just some stupid hoop jumping through exercise, in common with about

My tester, who I have known for several years, never pushes the pedal more than about 2/3rds of the way down. I always get the 'quick pass' and have given up on the annual boy racer routine now because I know what he will do!

Julian.

"Julian" gurgled happily, sounding much like they were saying:

From

Is that just for exhaust emissions, or does he do so for other areas of the car, too? Tyres, p'raps? Structural rot? Let's hope VOSA don't catch him at it, eh?

Yes, smoke being emitted may just be a build-up of particulate matter inside the exhaust - but it may equally be excessive emissions due to an injection fault. Are you suggesting that diesels shouldn't be subject to any emissions test? Or do you have a constructive proposal for an alternative test?

Oh do f*ck off. If you want a debate regarding particulate testing and alternatives then start another thread.

Julian.

My 306 passed it's MOT on bio no problem

I've always considered the test flawed. I'm old enough to remember old Fodens, Seddons Atkinsons and the like trundling up hills emitting clouds of black smoke, so I wouldn't want to go back to no testing, but the smoke always comes when the engine is working hard under load. Revving the bollocks off an engine at no load is a nonsense IMHO. No wonder when they started they knackered loads of engines. I'm sure a better way could be found.

Steve

"Julian" gurgled happily, sounding much like they were saying:

Oh, please forgive me for pointing out the slight flaw in your load of bollocks...

I'll tell you what, I'll cut it down to the basics if you like.

Banning diesels would be my suggestion. Horrible things.

But applying full throttle to a diesel at idle gives you full load.

ROFL.

I remember about 15 years ago when I had a Pug 205 Diesel. Prior to MOT I used to adjust the throttle cable outer sleeve (just a ''R'' clip and a number of grooves IIRC) so that full pedal travel gave about half pump lever travel.

It only revved up about 1/2 way and easily passed the smoke test. For the record it would easily pass the test ''properly,'' but I can't resist finding ways to fiddle the system and the Adrians of the world!

Julian.