[Markie]

Hi. I'm driving conservatively and getting around 59.5 mpg. 100 miles a week motorway and 50 around town. I have the instant fuel consumption on the dash all the time. If I'm driving in fourth gear at 30mph on a flat road I get between 60 -75 mpg, when coasting 99.9. Once a month (on the same journey) I notice coasting is at 70 and the 30mph is down to 43mpg. If I coast round a corner, it drops to 50mpg.  I know it sounds strange, but I knoe the car. It seems like it gets a cold once a month. Is the cold start sticking? Any advice.  I can afford the extra 50 pence of fuel a week lol, just niggling me!
Thanks
OCD Mark

[tw2005]

I'll throw a complete random and I have little to no knowledge on but do the UK models have DPF? Do these regenerate by injecting additional fuel into it to raise the temp and burn off? Just a thought other than an I have no idea response.

[xiziz]

Sounds exactly like a DPF regen, mine does it about once per tank. You will also notice a slight loss of power, usually only noticable at full load(eg going up steep hill). Unfortunatly Hyundai decided its better for us not to know when its doing regen by not having a light on the dash.

The fuel drain on coasting is the only way we know its running a regen cycle(and we are supposed to let it finish, which usually takes 20-25km).

[FatBoy]

I was going to say that it sounds like a DPF regen.  Increased fuel usage, and a possible unusual smell.

Our 4WD does it about once a tank as well (apparently).  The only time I knew that it was happening was when my wife got a warning on the dash to say "Continued driving mandatory".

[Markie]

Thanks for your comments guys. I thought there may have been a fault with the car. Today the fuel consumption is back to normal.  The google'd it and couldn't find a reason but I knew you guys would have the answer.

[Footski]

Would someone kindly explain what a DPF regent is?

[Dazzler]

Would someone kindly explain what a DPF regent is?

A DPF regen (short for Diesel Particulate Filter regeneration)

is process which needs to happen periodically to clear the build up of "soot" in the DPF ..

Google "Diesel Particulate Filter Regeneration" and you will get various explanations like this ..

How Diesel Particulate Filters Work

[Footski]

Thank so Dazzler. It just goes to show you are never to old to learn...

[Dazzler]

Thank so Dazzler. It just goes to show you are never to old to learn...

No problem. I certainly didn't know what they were until i became involved with this site almost 10 years ago.

I would like $1 for every word spoken about them on here in those 10 years.