Hi.dpf is blocked we've tried 70 mph down the motorway for 25 miles doesn't seem to have worked

Also becoming slow.foot down no power

Is dpf to blame

Did you maintain high engine revs or simply high vehicle speed ?

What is the exact model / engine of Focus you have ?

You have to be going 70mph with revs over 2500 to 3000 for a good 20 minutes that's how I sorted my dads out, do it late at night so you don't have to slow down

the speed is actually irrelevant although driving around at 30mph doing 3000 RPM might drive you and everyone around you a little crazy. I used to find 3rd gear at 60 was a good compromise, also means you don't need to slow down so much in traffic. A 20 min blast at 3000 RPM should get your exhaust temps up to where it needs to be.

Course you need to remember that the DPF is slowly and ultimately will kill your car.

Even if your car is full of soot, burning it as we are saying only turns it in to ash, which fills up the DPF as well, eventually you will get to the point were your unable to get the engine up to temp to help clear it which compounds the problem.

You have a 2008 car, assuming you drive the average miles a year of 12k your sitting at about 80k on the clock, which is after the point ford suggest you replace it.

Not meaning to alarm you or anything but, it is a ticking bomb and you should spend some time thinking about this before it is too late.

Yep, road speed is irrelevant, it's high engine speed that develops the heat required to initiate either a passive or active DPF regeneration

75mph (69 on sat nav) in 4th is 3k rpm on the 1.6. I had a regen kick in on 2 short journeys in town last week (who designed the regen software on these!!) so went out of my way to help it the third time and kept it over 3k for 20 minutes on the dual carriageway, forcing people out of the way like a BMW driver haha...the noise and smell were horrendous BUT it does seem to have made a large improvement compared to the normal active regens that I don't 'help' usually! I also lost 5mpg on the trip computer doing that. Stupid DPFs. :(

If it's blocked with ash you're just causing more problems tryin to make it regen though, as Dee says it may need replacement.

Passive & active DPF regenerations are not fuel efficient but who cares about a temporary dip in MPG compared to the cost of either cleaning or God forbid buying a new DPF

Quite why these contraptions don't have a little gas tight hatch that can be opened to remove ash defies logic

Passive regens are efficient enough, its just your action of driving that heats the DPF without any extra input. This never works in reality though, not from my live testing anyway.

So it always needs active regens, whether that's initiated by the PCM while driving or by a computer at a standstill. Either way, you're burning fuel (causing soot and raising other emissions) to burn the soot in the DPF. It's a daft system really.

I care about the loss of MPG...the MAIN reason for me owning diesels is fuel economy. Its not a temporary loss either, it's considerable over the tankful. I'm certain I'd get 60+mpg average on the Focus without a DPF.

It's not only the regens that reduce mpg, the DPF itself causes a massive restriction in the exhaust, it's not like a cat where gas flows through, in a DPF the gas has to be forced through, so it 'wastes' engine power forcing the exhaust out.

It's not really possible to add a hatch to clean the ash out, but some of the Peugeots use a separate DPF to cat, means you can easily take the DPF off the bottom and clean it or replace it fairly cheaply as it's the cat that costs the money in the combined DPFs. Why they don't all use that system I really don't know!

I agree with you on the power restriction caused by DPF's - that's why my TXS is remapped & now it performs as Fraud / Peugeot intended :)

No remap required on my Focus :)

Haha, I can only dream of fuelling an ST myself currently! One day though... :D

It's err , , , , not economical :) averaging 30 MPG , , do I care , , Nope !

Edited August 26, 201510 yr by MONDEO TXS 2.2

You get 30MPG from a Focus ST? Good effort! :)

Yes I do, but only on a Monday , , , , , :)

Mondays are when it gets cleaned , , , , , :)