Doctor Diesel

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Web03I wonder if The Doctor might offer me a few words of advice on whether, in view of all the problems with diesel particulate filters (DPFs), I should look at having mine on my 2013 Focus Zetec 1.6 TDCi taken off, as I believe is still possible? Will it save me enough fuel to cover the cost, over a reasonable period?
Norman Gould

A few words, you request. Here they are: “Don’t do it!” As you should know, this practice is illegal. In essence, your car will simply fail its first MOT test in 2016, if you still have the car then, and if the MOT station does its job properly. You would be unlikely to save enough fuel to cover the cost of removal, and it would certainly cost you more than it would in fuel and time to take your car out for the regular exercise that would ensure that your DPF was working efficiently and regenerating as required. The likelihood of you actually being stopped on the road, your vehicle inspected, and you being prosecuted for having an illegal car is actually pretty infinitesimal, but that’s because, as yet, there’s simply no real inclination or manpower to enforce the law properly in the matter of vehicle emissions controls. We have little or no idea (because there’s so little monitoring) of how much urban pollution is being generated by cars and other vehicles (HGV in particular) that have been illegally modified and which, as a result, pour out grossly excessive and illegal emissions of particulates and oxides of nitrogen. The annual testing and policing of HGV emissions is still pathetically inadequate and does little or nothing to ensure that emissions control equipment has not been meddled with or removed. Maybe the London air quality panic will change this.

4 Responses

  1. There is no need to remove the dpf nor pay for its replacement, simply have it professionally cleaned which is done without removing by injecting the cleaning agents into the pressure sensor connection.

  2. There is a laboratory proven diesel additive that I use for my wife’s car (which does a lot of short journeys) to help keep clean and clear the dpf. It is called Envirox. It was developed at Oxford University and claims to be able to assist in removing excess soot deposits from the DPF by reducing their ignition temperature. Seems to be backed up by scientific tests. I have found it effective in getting the DPF light to go out on her car after relatively short fast drives. Regular use apparently will reduce blockages occurring, even if a mainly short journey driving style is common. Try looking for Envirox DPF assist and their routine fuel additive Envirox. I have no financial interest in this company, although I did once work for Oxford University – where I heard about this from an academic. Not the cheapest additive, but my experience is that it appears effective. Perhaps Dr Diesel may want to look at this for a special issue on additives?

  3. It is not a good idea to fiddle with emissions control systems.
    Just ask VW/Audi, they are facing criminal proceedings in the USA, they sold almost half-million-diesel VW/Audi cars between 2009 and 2015 with a “defeat device” in the ECU computer.
    The defeat device allowed the cars to recognize and pass emissions testing compliance, without the device Nox output from the exhaust became 10 to 40 times the legal limit.
    VW/Audi could be fined up to $37500 per car i.e $18 billion.

    Here is the Notice of Violation served to VW / Audi

    I guess it is not just VW/Audi who have such defeat devices in their diesel car Nox control ECus and the problem is probablu Industry-wide

  4. The reliability and long-term life of a DPF is subject to additional scrutiny since VW group were caught in the USA.

    The VW diesel expert J R Laing, Head of Diesel Competency has pleaded guilty to charges over USA violations and also revealed 6 levels of VW defeat device including an ECU software update rolled out to vehicles as a response to high warranty claims for the VW DPF, the software update cut back emissions control to prolong DPF life at the expense at even greater violation of the Nox standards, basically if correct and proper emissions control is implemented in a VW, as opposed to the dyno test situation , then the VW DPF will simply fall apart

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