DPF Query

[TMan77711]

just wondering how MOT testers can check for presence of DPF during MOT test without opening DPF casing to check it has not been gutted. Any comments?

[green van man]

Think if it looks as if its there then it all depends on the emmition readings.

Of course that sort of mod would be frowned upon by insurance company IF they found out.

Paul.

[dingov70]

Testing for dpf is done by looking for a dpf if one was fitted at the factory , if the core has been removed & the can welded up again and the tester can see it has been tampered with you get an automatic fail . A modern diesel should easily pass the smoke test . To the best of my knowledge , there are no seperate smoke particulate figures for diesels fitted with or without a DPF


This iswhat the tester looks for ( readings wise )


Diesel Fast Pass
Since 1 August 2002 a metered „fast pass. procedure has been used to help simplify and reduce the time taken for the test, allowing vehicles with low smoke emissions to pass the metered test after one acceleration of the engine. If, after the first acceleration, the meter reading is at or below 1.5m-1, the vehicle will pass the meter test.

The smoke meter will indicate to the Tester to accelerate the engine. The accelerator pedal will be depressed quickly and continuously but not violently, to reach the full fuel position in less than 1 second. After the release prompt is given, the Tester will immediately release the throttle. The meter will calculate the maximum smoke emission during the acceleration and display the result. If the smoke level reading is at or below 1.5m-1, the vehicle has passed the metered test, and a pass result will be displayed on the meter.

Standard diesel test
If the smoke level reading is greater than 1.5m-1, a further two accelerations will be requested by the meter. Provided the average of the 3 tests is at or below the appropriate limit in Table 3, and the three results are within a specified tolerance of each other, the vehicle will have passed the test. The Tester will stop the engine and remove the smoke meter probe from the tailpipe.

Where the average smoke emission at the end of the third acceleration exceeds the limit in Table 3, the meter will request further tests. This will continue until either the average of the three preceding accelerations is at or below the limit in the Table or a maximum of six accelerations have been completed. Once the vehicle has either passed the test or a maximum of six accelerations have been completed the Tester will stop the test and remove the smoke meter probe from the exhaust tailpipe.

As a final check the Tester will assess visually whether the smoke emitted from the exhaust, regardless of measured smoke density, is likely to obscure the vision of other road users. If it is likely to do so the vehicle will fail the test.

[TMan77711]

What happens if the DPF is hidden behind a guard below the engine and not visible?

[rudi dudi]

In a word no the Mot won't have a clue you've reamed the guts out ..

Delete the bloody thing is the best you can do.. Now you will most likely be sent to hell for even thinking of such thing with the Do gooders and the that's illegal ( blah F**kin blah brigade that can be found on here)..

I will most likely be sent to hell with you for even suggesting it!!!

Dpf delete that's the motto I roll with.:

[dingov70]

I have heard talk that testers will at some point in the future plug into the OBD port & interrogate the system to ensure the DPF software is still installed & functioning i.e. providing live feedback to the ECU . that would clearly lead to an immediate fail come MOT time . If you have a shield in place obscuring the dpf / cat / whatever , the tester in NOT allowed to dismantle any part of the car for inspection , so make a metal shield & cover your "naughty" actions up , one that sits like an umbrella over the top of the DPF to obscure the welds would be perfect . I blocked my EGR's on my none common rail diesels , gutted the Cat's & fitted "heatshields" on top of the cat to hide the welds & held them in place with jumbo jubilee clips & simply told tester i had made them to reduce noise & heat transfer to the floorpan . He smiled & moved along

[TMan77711]

Hi dingov70. Currently in N Ireland where I live we only have the DPF visual check by MOT testers. If the DPF has been gutted and carefully rewelded and hidden in a way that it cant be seen during inspection then it will pass. We don't use garages here but instead have special government MOT centres. I guess it will only be a matter of time until we get as tight with this as the rest of thr UK. I guess when my DPF does fail I may just replace it with an after market one to avoid any hassle. Thanks. T.

[rudi dudi]

As there isn't a single scan tool on the market that can 100% talk to every vehicle regardless of age or manufacturer, I really wouldn't worry about a plug in diagnostic detecting a Dpf delete..