It is possible to remove the diesel particulate filter which is responsible for all your troubles.

However, you do need to have the engine management file ("engine map") altered, in order to remove the "regen" process.

Confused? Read on. We would like to explain what the problem is, what is likely to have caused it, and what services we can offer to provide a permanent solution. The new modern diesel vehicles don’t seem to ‘smoke’ like they did ten years ago. In reality, they do. Yes, things have objectively improved, but an ingenious plan also ensured that the problem is tackled, at least on the surface.

The plan involves ‘catching’ all the black soot via a filtering device, while one drives around town. Then, when the car is being driven at higher speeds, whatever has been collected in the filter would be blown out and expelled. So, in the name of the environment, (and as that soot has to go somewhere), an entire month worth of soot is going to be dumped on the side of the motorway, or in the countryside.

If you ever see a modern car belting down the motorway, emitting a cloud of smoke, the chances are that its engine is spot on, but that its ECU is performing a ‘regeneration cycle’.

On modern DPF (Diesel Particulate Filter)- equipped engines, the regeneration cycle does not perform anything more complicated than pumping in vast quantities of diesel into the exhaust side of the engine, (far more than could ever be burnt properly), in an effort to heat up the DPF enough to blast its contents out the back of the car and into the air vents of the poor driver following it.
There are two most likely causes for a blocked DPF.

The first, and most common, is your journey type and driving style. Perhaps the DPF (or ‘soot catcher’) has been doing its job properly. However, it may have been a long time since a decent, constant speed could be maintained, or a continuous run in top gear (as you would on the motorway). The ECU of your engine will not have cleaned the DPF out. Therefore, a lot of town driving and simple commuting to and from work, dropping the kids off at school etc.., may result in a DPF that is unable to clear itself.
Of course, one could try to go on a long run, to keep the DPF clean and healthy. But that may not always be possible or easy to do; and once the ‘limp mode’ has set in, it is rather difficult to go down the motorway for a blast.

The second reason why the DPF may fail is that it has simply come to the end of its natural life. Even if you have driven plenty of motorway miles and you have been lucky to have experienced a chain of successful regenerations, a DPF will not last forever. Each ‘regeneration’ will leave a very fine layer of ash residue behind, and this will become the cause of the ultimate blockage.

Further forced regeneration cycles will not clear this. These units are a serviceable item and will need replacing sooner or later.




The picture above shows a typical example of a blocked DPF core that we have removed from an Alfa Romeo/SAAB engine. The core fills the entire canister: one can only imagine how hard the engine has had to work to push the gasses through it. The more blocked it gets, the more back pressure it causes. The owner of the vehicle sporting this DPF had been complaining of poor fuel economy and performance for a while. Now he understands why.




Picture 2 (above) shows the EXIT end of the same DPF. The photo shows clearly that there is a blockage between the core and the exit, as well as the restrictive environment present even in a brand new DPF core. This affects the engine efficiency and its fuel consumption.



The picture above is of a cross-section of the same DPF. This particular unit had in fact been working very efficiently, as the white areas shown are ash. This means that the black soot particles had, in fact, been successfully reduced by many regenerations. Each time the DPF goes through this cycle the extra fuel that gets pumped in creates such a temperature that it reduces the soot particles to nothing but ash. In the end though, no matter how efficient, you cannot reduce ash any further and it starts backing up.



This DPF was reduced to a solid lump of ash that was literally chocking the engine: no wonder the car broke down on its way to our workshops.

THIS DPF WAS NOT FAULTY - IT HAD REACHED THE END OF ITS SERVICEABLE LIFE. This is the filter used on The 1.9 Diesel Turbo 16V engine used on the Vauxhall 1.9 CDTI, Alfa Romeo 159 JTD and the SAAB TiD engines. This one had covered 80k miles Yes. See Angel Tuning in the press below.



A.T Facebook, www.facebook.com/remapping



Well... you can either replace it or remove it. If, however, you have this problem because of your urban driving habits, you are likely to suffer a repeat of the problem with the next one. A new DPF will cost a four figure sum from the main dealer.

However, you can have it removed altogether. Angel Tuning has done so repeatedly, and the procedure is catching on: in the last three months of 2012

DPF removal work at Angel Tuning has increased by 600%, in comparison with the same period of time in 2011.

Removal is considerably more cost-effective than an outright replacement, and it is a permanent fix.
Well.. no. There is often a substantial amount of work involved to remove it: the car needs to be raised from the ground, and a number of workshop specialist tools are used to perform the removal. Once the DPF has been removed, the engine’s management system has to have the regeneration process (inbuilt in its memory) removed from it. Angel Tuning now offer a vast array of automotive services from our Banbury headquarters. At this location we can offer full workshop facilities to cater for your needs, from a straightforward service, engine tuning or damage repair to complete vehicle restoration and race preparation. Whatever your needs may be, talk to us as we may be able to provide a cost-effective solution.