Diesel Particulate Filter Solutions

What is a DPF?

A DPF (Diesel Particulate Filter) also known as FAP on some French vehicles, is a device fitted to the exhaust system of modern diesel vehicles to reduce emissions and meet European emission standards. It does this by trapping Soot (Particulate Matter) from the exhaust gasses while letting the gasses flow through the system.
As with any type of filter a Particulate Filter needs to be cleaned regularly to function properly. With DPFs this is done by a process known as Regeneration which involves a combination of a Catalyst function in the system and burning the soot to gas at a very high temperature leaving behind an Ash residue within the DPF. Regeneration should be an automatic process taking place in the normal use of your vehicle.

Problems encountered with DPF

If regeneration doesn’t function properly it leads to a build-up of soot affecting performance and fuel economy. Left unattended, this will result in a Blocked DPF which can ultimately cause very expensive damage to other engine components.

A blocked DPF is also potentially dangerous as it can cause overheating in the exhaust system and cause a fire risk. To prevent this damage, most newer vehicles will go into “Limp Home” safety mode at this stage, meaning the vehicle will have minimum power barely sufficient to crawl home.

For regeneration to take place it requires the vehicle to be driven regularly at some speed on open roads e.g. motorway driving, typically driving at around 2500 RPM for approx. 30mins at least once a month, this will keep things working.

However, many diesel vehicles are used primarily in urban areas or on short stop start journeys e.g. local deliveries, taxi’s, school runs etc. and many have auto gearbox, so the vehicle does not get the chance to heat up sufficiently and is unable to carry out a full regeneration process.

Legal Requirements and the MOT Test

From February 2014 the inspection of the exhaust system carried out during the MoT test will include a check for the presence of a DPF.

A missing DPF, where one was fitted when the vehicle was built, will result in an MoT failure. A vehicle might still pass the MoT visible smoke emissions test, which is primarily intended to identify vehicles that are in a very poor state of repair, whilst emitting illegal and harmful levels of fine exhaust particulate. It is an offence under the Road vehicles (Construction and Use) Regulations (Regulation 61a(3))1 to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet.

Request A Call Back

Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use. The potential penalties for failing to comply are fines of up to £1,000 for a car or £2,500 for a light goods vehicle.
We can offer you the following three options:

1: DPF Replacement - Replacement of the filter using an OE matching quality part
2: DPF Cleaning - Carry out a chemical clean of the existing filter using Tunap’s patented particulate filter cleaning system with which clogged particulate filters can be cleaned in an installed condition, rapidly, simply and significantly more economically than replacing them.
3: DPF Recalibration - If you have had your DPF core removed, we may be able to recalibrate your vehicles ECU to stop your engine going into limp-home mode and clear the DPF warning light. Customers must be aware of the legal implications as stated above.


What else should you know about your DPF

The DPF is closely linked to other components, if these do not work properly, they will aid in blocking the filter. A blocked DPF can also damage your turbo, due to the excess amounts of back pressure created. During the regeneration process, some engine inject excess amounts of fuel in an attempt to heat the DPF up to allow regeneration.

This process can cause the extra diesel to leak into your engine oil, and could potentially destroy your engine. Work on DPF can be quite complex and should only be carried out by professionals with the correct specialist equipment.