Poor MPG

[Big Sig]

Last night I filled up to the brim with diesel and drove 112.7 miles home and filled up again. I used 15.9 litres for that journey. Now my working out gives about 32mpg.

The route i took was down the fosse way from Coventry to Trowbridge in Wiltshire, plus a few local miles. The car is a 3.0 CDTi signum manual on an 03 plate.

Does anyone have any ideas as to what would be giving me such poor mpg? The cruise was set at 60 mph for most of the route. Would it be because of the route, lots of hills and the odd town? I have no spanner light on, the car was serviced a couple of thousand miles ago. It doesn't bother me too much tbh, but was wondering if any other V6 diesel owners could shed some light on this?

Before any of you post, I'm not bothered that your 1.8/2.2/2.0t/3.2 v6 may or may not do better mpg :

many thanks

[parapaul]

IME hills don't have a massive impact on consumption because the ups generally get compensated by the downs but town driving has a huge detrimental effect.

How much of that 112 miles was through town as opposed to nice steady NSL roads?

[spennny]

Cruise Control uses more fuel as you start to go uphill, to keep the speed set, its ok, on long straight and even downhill,

Uphil, i turn CC off and use the pedal
Seems to help

[parapaul]

Uphil, i turn CC off and use the pedal
Seems to help

Eh? How on earth can that help? Surely you use the same amount of fuel whether you maintain your speed or the CC does?

[spennny]

Do you ever watch the MPG / Inst Consumption on your dash when you approach a hill, Try it

[chrisf70]

That was why Clarkson turned the cruise off on that A8 he was driving to Scotland in. He said the cruise would eat the fuel rather than using your foot.

[ceptimus]

If you allow the speed to decay as you climb short hills, and then build up again as you go down the other side, that is more economical than keeping at a constant speed.

Of course, on longer climbs, this is of no use.

[_ZS_]

Cruise Control isn't smooth enough. It'll let speed drop too much then try to accelerate quickly to get back up to speed, then goes past the preset, slows down, speeds up, yadda yadda. A driver can anticipate hills and feed power on smoothly to maintain the speed without galloping fuel.

[Big Sig]

IME hills don't have a massive impact on consumption because the ups generally get compensated by the downs but town driving has a huge detrimental effect.

How much of that 112 miles was through town as opposed to nice steady NSL roads?

Probably 50:50 to 70:30 nsl to 30/40mph.

Cruise Control uses more fuel as you start to go uphill, to keep the speed set, its ok, on long straight and even downhill,

Uphil, i turn CC off and use the pedal
Seems to help

Maybe I should try it with the cc off. It was on most of the time and I do remember the clarkson A8 thing. Next time I'm gonna try the motorway, its further but should give a smoother journey

[parapaul]

I tend to use the motorway to get to work for the same reason. It's only 1 junction, but 15 miles at a steady 70mph does waaaaay more for my consumption than the 12 miles of 40mph, traffic lights, roundabouts etc.