HEADPHONES Posted August 6, 2012 Share Posted August 6, 2012 I remember reading a thread recently where someone posted info on diesel particulate filters. If I remember correctly it went along the lines of the filter collects the particles and they get "burned off" during a long run. My mate has been told this filter is throwing a cel light on his 3.0 diesel A8. Can a good run at high revs clean the filter, and if so what constitutes a good run in terms of time and rev range? Also, having a diesel as my family car should I be taking it for some canage on a regular basis to keep the filter in good nic? Any advice welcome guys (and gals) Quote Link to comment Share on other sites More sharing options...
rtbiscuit Posted August 6, 2012 Share Posted August 6, 2012 the DPF only burns off when the engine is running high. i.e. good long drive. in basic terms it flushes the DPF with fuel and then burns it off. hence why you get improved mpg when you have them removed and a tube put in.i know some longlife custom exhaust builders will do a CFP removal and decats (as you don't need cats to pass an MOT on a diesel) they often throw upCEL's if the car is used for lots of round town driving. doesnt do the long jaunts that are needed for the DFP to clean itsself Quote Link to comment Share on other sites More sharing options...
HEADPHONES Posted August 6, 2012 Author Share Posted August 6, 2012 Cheers Mr Biscuit I have told my mate to do a couple of laps of the M60......Manchester's version of the M25. Quote Link to comment Share on other sites More sharing options...
rtbiscuit Posted August 6, 2012 Share Posted August 6, 2012 Cheers Mr Biscuit I have told my mate to do a couple of laps of the M60......Manchester's version of the M25. a long run might clear it, depends on how clogged the filter is, if they get to bad without a burn off it can mean a replacement. i know when i was on the alfa forum alot of the diesel guys had the DPF removed as it had so many issues. and was mentally expensive for a new one. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted August 6, 2012 Share Posted August 6, 2012 Our Alfa has one. The chaps in service reckon that anything over a good 40MPH when warm will start to clear it out or keep it clear, but you need to be doing above 40 as a constant speed. Stop/start driving is what kills them. As Rich says, it depends how bad it is, if its already really clogged then certain "pathways" through the filter may never be cleared as the gas takes the path of least resistance. Alfa said to us to do a good run at least once a week if you town drive, and more often if you can. In fact we have a leaflet about it somewhere, I'll see if I can find it and take a scan of it. I seem to remember it tells you if it starts to get clogged and tells you to drive at a certain speed for a predetermind time. Quote Link to comment Share on other sites More sharing options...
KyleR Posted August 7, 2012 Share Posted August 7, 2012 Mate has the same problem with the womans BMW, he has to take it for a good blast to Belfast and back on the M1 (28 miles each way) to get the light off. To me this kind of destroys the point of them lowering emissions when you have to drive an extra 60 miles in one gear lower to get the light to turn off, thus raising your carbon footprint because you wouldn't be doing that extra drive otherwise Quote Link to comment Share on other sites More sharing options...
rtbiscuit Posted August 7, 2012 Share Posted August 7, 2012 my advise is get it removed and a bypass put in, means better mpg and more performance special if you decat the exhaust and have it chipped Quote Link to comment Share on other sites More sharing options...
Chris`I Posted August 7, 2012 Share Posted August 7, 2012 Yeah if you are constantly having to go out for a blast to make the light go out, it wont take too long to pay for the DPF bypass pipework. I would get this done to the Alfa but compared to the Zed it has way better MPG anyway and enough performance to tow the bikes, so we're happy with it (for now ) Quote Link to comment Share on other sites More sharing options...
Lexx Posted August 7, 2012 Share Posted August 7, 2012 It was the bane of my life when I had the Pug coupe. It got to the point with mine where I ended up dismantling the exhaust to get at it and pressure washing it out. Lasted 4 months. Removed it in the end, and reprogrammed the ECU to get rid of the CEL it threw up because it wasn't there. Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted August 10, 2012 Share Posted August 10, 2012 You also have to use special oil in the car if you have a DPF. On our shed 307HDI it has a DPF and the oil we have to use costs nearly twice the price of the oil we could use had it not got a DPF. Quote Link to comment Share on other sites More sharing options...
Chris`I Posted August 10, 2012 Share Posted August 10, 2012 You also have to use special oil in the car if you have a DPF. On our shed 307HDI it has a DPF and the oil we have to use costs nearly twice the price of the oil we could use had it not got a DPF. Ah so thats why they laboured the point about using the right oil. They kept banging on about making sure you use the right oil but didnt say why, just said we had to "or stuff breaks!" Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted August 10, 2012 Share Posted August 10, 2012 You also have to use special oil in the car if you have a DPF. On our shed 307HDI it has a DPF and the oil we have to use costs nearly twice the price of the oil we could use had it not got a DPF. Ah so thats why they laboured the point about using the right oil. They kept banging on about making sure you use the right oil but didnt say why, just said we had to "or stuff breaks!" Yep and I dont know if all cars are the same, but on our 307 HDI it has some other special oil stuff in a reservoir near the fuel tank, which is what it injects into the DPF to burn the soot etc. Now, when that runs out apparently you can only buy that oil from the main dealer and its something ridiculous in price. I seem to recall £200 being the sort of price mentioned. A lot of people remove the DPF, but im not sure if its now like with CATS in that if your car was fitted with one you have to keep it. When I had my golf GT TDI i threw the cat/particle filter away as there was no test in the MOT for cats or particle filters, as that was only done on petrol cars. Quote Link to comment Share on other sites More sharing options...
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