[davidST357]

Evening all,

Just bought a 2016 focus st3 diesel which has covered 16k miles, I've had it a week and today after a long run I came off the motorway and was at the lights when the car sounded very rough, the exhaust was burbling alot more and I caught a slight whiff of burning fuel in the cabin, it sounded so different that I thought some boy racer with a saxo big bore exhaust or something was behind me. I got home seriously worried and it carried on for a few minutes then stopped. No warning lights or system fail messages. Could this be the dpf regenerating? I've Always had petrol St's so apologies for the lack of knowledge.
Cheers
David

 

[GrG]

Yip, everything you described is a classic regen symptom. Enjoy the fruity soundtrack, ;-)

 

[Drsdriver]

Definitely DPF .
When you got home, did you turn the engine off , then it stopped or did you sit on your driveway with engine idling then it stopped on its own accord?
The reason I ask is thats its very very important not to interrupt the DPF regeneration whilst its regenerating.
It uses more fuel at that particular time and if it gets stopped midway it will dump the un burnt fuel into your oil sump.

Not a good combo, also then it means the dpf was not cleaned and it will try it again once the engine up to temp.

There is only so many attempts until the dpf is saturated with soot and then its a garage job with a very expensive bill.
Best to keep driving round the block if you hear it again and your near home. Definitely dont turn your engine off.

Enjoy your new motor thou, I love the grunt of the diesel. Its sooo addiictive .

 

[davidST357]

Cheers for the replies.
Yes left It running for a while I'd say it lasted just over 30 minutes or so from when I heard it. Came back out to it later on and everything was fine. I've been averaging 44 mpg on A Roads and some motorway in the last week which is refreshing compared to the Mk2 ST I had which was around 20.
Certainly will enjoy it thanks.

 

[Igg]

Hi, How often is dpf regenerated? Are there other symptoms besides increased noise and higher fuel consumption?

 

[Bigayal]

Hi, How often is dpf regenerated? Are there other symptoms besides increased noise and higher fuel consumption?

I don’t know about how often , but if when you stop your fans are going for it then it was in the middle of a regen

 

[Radiator]

There’s a Transit owner who put a video on Youtube saying that when Transit regens start, the ecu also activates the heated screen, putting more load on the engine. He then fitted an led across the heated screen connection which shows him when the regen starts.
I‘ve seen similar with other owners of different make and models where the heated mirrors turn on. I’ve wired in an led to see if it‘ll show if the Focus activates its heated mirrors too.

 

[sttwoton]

More often, the more miles your engine has on it, at least your fuel vaporiser isn’t blocked (very common on these Peugeot engines), that would have put a light on, but not gone into limp mode.

 

[Kevin_Mc]

I've had my diesel ST for over two years now and I've never noticed a DPF regen happening. I've never once got home and left it running in the middle of a cycle, just turn it off and get out. How can I tell when it's doing one? Most of my daily milage is on the motorway, usually at a fair rate of knots so it should be the perfect time to do it then.

 

[WayneST-2]

I've had my diesel ST just over a year, used to notice the DPF regen quite clearly, same as you described, a noticeably louder exhaust note and fuel consumption would go down, I'd say mine was doing it maybe every 500 miles or so, brought mine at 58k, now around 80k miles, so quite a bit more mileage than yours.
As other have already said, there's no visual indication as standard when it regens, just the noise. I think one way you could visually notice, maybe with a bluetooth ODB reader connected to your phone running Forscan or similar, then monitoring the DPF load figures, which will increase steadily until regen starts, then take a sharp decline whilst in regen, then start the cycle over again.
I've not really noticed the increased exhaust noise as much since fitting the RS Airbox Lid, as the increased noise from that is pretty constant and doesn't sound too dissimilar to a louder exhaust.
I've never been particularly careful with waiting for the regen to complete before switching off, no immediately apparent side affects of doing this, but as others have said, it's probably not recommended and maybe slowly causing issues that aren't immediately noticeable.
Depending on the the end point of your journey, it's not always practical to keep driving or leaving the engine running until it completes the regen.