diesel emissions testing.
Discussion
Smoke tests are about to be introduced here as part of the MOT. I think they did try this a few years ago, but after a lot of engines blew up, and some legal action ensued, they stopped.
The new test involves holding the engine on the limiter for 5 secs, and monitoring smoke emissions.
I assume this is what is done on the mainland ??
Why have they chosen a test that is so abusive towards the engine, and such a scenario would NEVER be repeated during normal usage ?
What comeback to you have, if an engine fails whilst undergoing the test ??
Must check owners handbooks, but I'm sure I read somewhere, never to hold a diesel engine flat out, with no load on it ?
The new test involves holding the engine on the limiter for 5 secs, and monitoring smoke emissions.
I assume this is what is done on the mainland ??
Why have they chosen a test that is so abusive towards the engine, and such a scenario would NEVER be repeated during normal usage ?
What comeback to you have, if an engine fails whilst undergoing the test ??
Must check owners handbooks, but I'm sure I read somewhere, never to hold a diesel engine flat out, with no load on it ?
I'm not sure about actual engine failure, but it is actually up to the mot tester to make sure that timing belt is in good enough order to withstand such a test and if the belt fails under high revving whilst in an mot station there are appeal procedures set out to claim compo. I presume it would be the same. Maybe we should lengthen our throttle cables for the test 
then the tester would not be able to get above 2000rpm Unless your motor is on fly by wire then i suppose you're buggered.
Regards, Paul.
then the tester would not be able to get above 2000rpm Unless your motor is on fly by wire then i suppose you're buggered. Regards, Paul.
TBH I've never had any probs with the test. The rev limit on a diesel is low and they're strong engines. The onus is on yourself to ensure the cambelt has been changed at the prescribed time. I would state that only shagged engines will break when revved.
The smoke testers are unreliable though, in my experience. One time when trying to get my Astravan through, it was revved 17 times. But it was no sweat, they could do it all day long if they wanted to. Not a hint of smoke either.
Do take your car for a blast beforehand though, to clear out all the soot in the exhaust pipe. Thats the wonderful thing about this farcical test, in the name of the environment you have to blast all that accumulated muck out into the environment.
The smoke testers are unreliable though, in my experience. One time when trying to get my Astravan through, it was revved 17 times. But it was no sweat, they could do it all day long if they wanted to. Not a hint of smoke either.
Do take your car for a blast beforehand though, to clear out all the soot in the exhaust pipe. Thats the wonderful thing about this farcical test, in the name of the environment you have to blast all that accumulated muck out into the environment.
I can only presume that when the vehicle is being revved on its limiter, that it is at its optimum speed, thus expelling the worst amount of gases it is able to do so. Also, what class test would your vehicle require?? Over here, a class 7 test which is basically twin wheel Ford Transit size, it is only a visual test. Only class 4 tests (small cars & Vans) undergo this test. But i definately understand your concerns mate.
Info sheet supplied from DVTA.
The metered smoke test has been carried out in EU countries for many years. During this test a calibrated smoke meter is used to assess the density of smoke fromm compression ignition engined vehicles.
the engine will be accelerated up to teh governed speed and the smoke density measured. Engines that emit very little smoke will achieve a meter reading of 1.5m^-1 or less and will pass he test after the first acceleration, however if the test is not passed on the first acceleration, then a further two tests will be required.
The average of the three acceleration readings will be calculated and if the reaidng is at or below 2.5m^-1 for non-turbocharged engines, or 3.0m^-1 for turbocharged engines, the vehicle will pass this element of the test.
However, if the average is higher, a further acceleration will be carried out, and the averageof the last three readings will be calculated. This will continue up to a maximum of six accelerations. If teh average of the fourth, fifth, and sixth accelerations is higher than the appropriate level, the vehicle will not pass the test.
In addition, vehicles may be refused a certificate if the exhaust emits excessive smoke or vapour, to an extent likely to obscure vision.
A metered smoke tst will not be carried out if:
* The exhaust tailpipe is damaged or an accessory fitted which prevents insertion of the smoke meter probe.
* The exhaust system is extensively fractured or holed.
* There is obvious signs of an engine defect, such as unusual noise or emission of excessive smoke.
* There is insufficient or excessive amounts of oil in the engine, or low engine oil pressure, which could cause engine damage if teh engine is accelerated.
* There is obvious signs that the governors have been tampered with, or are not operating.
* The vehicle owner/presentor cannot confirm that the vehicle has been properly maintained, the camshaft drive belt has been replaced at the reccomended intervals and the engine is in a suitable condition for testing.
In the above circumstances where a metered smoke test is not carried out the vehicle will be refused a certificate.
NOTE:
It is important that vehicles are properly maintained prioer to testing ( including changing of the camshaft drive belts in accordance with the manufacturer's recommendation ) and presented for tst at normal working temperature. this may require the engine to be kept running prior to the start of the test.
Jeeeez, such amount of typing !!!!
The metered smoke test has been carried out in EU countries for many years. During this test a calibrated smoke meter is used to assess the density of smoke fromm compression ignition engined vehicles.
the engine will be accelerated up to teh governed speed and the smoke density measured. Engines that emit very little smoke will achieve a meter reading of 1.5m^-1 or less and will pass he test after the first acceleration, however if the test is not passed on the first acceleration, then a further two tests will be required.
The average of the three acceleration readings will be calculated and if the reaidng is at or below 2.5m^-1 for non-turbocharged engines, or 3.0m^-1 for turbocharged engines, the vehicle will pass this element of the test.
However, if the average is higher, a further acceleration will be carried out, and the averageof the last three readings will be calculated. This will continue up to a maximum of six accelerations. If teh average of the fourth, fifth, and sixth accelerations is higher than the appropriate level, the vehicle will not pass the test.
In addition, vehicles may be refused a certificate if the exhaust emits excessive smoke or vapour, to an extent likely to obscure vision.
A metered smoke tst will not be carried out if:
* The exhaust tailpipe is damaged or an accessory fitted which prevents insertion of the smoke meter probe.
* The exhaust system is extensively fractured or holed.
* There is obvious signs of an engine defect, such as unusual noise or emission of excessive smoke.
* There is insufficient or excessive amounts of oil in the engine, or low engine oil pressure, which could cause engine damage if teh engine is accelerated.
* There is obvious signs that the governors have been tampered with, or are not operating.
* The vehicle owner/presentor cannot confirm that the vehicle has been properly maintained, the camshaft drive belt has been replaced at the reccomended intervals and the engine is in a suitable condition for testing.
In the above circumstances where a metered smoke test is not carried out the vehicle will be refused a certificate.
NOTE:
It is important that vehicles are properly maintained prioer to testing ( including changing of the camshaft drive belts in accordance with the manufacturer's recommendation ) and presented for tst at normal working temperature. this may require the engine to be kept running prior to the start of the test.
Jeeeez, such amount of typing !!!!
I'm pretty sure they have notes pinned up on the wall at mainland MOT stations saying that they're going to rev the crap out of your diesel and that it's the presenter's responsibility to ensure the engine is fit for the test. If you don't want them to do it, don't get it tested! Quite what you're supposed to do instead isn't actually made clear!
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