Heavy fuel consumption?

We recently changed our 2010 2.2L 120bhp Symbol for a 2015 2.2L150bhp Kemerton XL with only 6,000 miles on the clock. The Symbol used to return about 32mpg, but the admittedly heavier Kemerton XL gets no better than 25mpg, no matter how I drive.  These are the figures indicated on the dash, not a proper brim-to-brim test.  Nevertheless, it's a bit disappointing and seems significantly worse than the typical figures other owners report. The 150bhp engine doesn't exactly feel much livelier, though of course the XL body is heavier. Changing a faulty air intake temperature sensor hasn't improved matters other than eliminating the engine management warning. So I am wondering if there might be some other fault. Can anyone suggest a "diagnostic plan"? Thanks for all and any suggestions.

Sounds familiar. Our Nuevo ES (with the aerodynamic properties of a breeze block) shows on the dash 24mpg. It has the 130bhp engine. 

Cymro

I too am mystified by the high figures that some folk on here achieve. I accept that our vehicles are heavy and have the aerodynamics of a brick so hills, headwinds, high speed and heavy acceleration will all have a very adverse effect. My van has achieved only around 26mpg until the last year or so when I have noted a marked improvement to around 29 or 30 so perhaps the engines take around30,000 miles to loosen up. Iam aware that manufacturers design the engine management systems software for stability rather than economy (unless it is for the vehicle on which published emissions will be checked!) so that could account for some of the variability between vehicles. However, I will never understand how some users can get mid to high 30's from their vans unless they drive solely on long journeys at a steady 40 to 45mph in flat country with no traffic.

I’m only slightly better off than the OP at 26.5mpg

Recent thread on consumption.... [You must be registered and logged in to see this link.]

The VWs are noted for mid 30s mpg and I wouldnt argue with say a Trident owner claiming 35mpg.
Regarding the rest as others have suggested the only true way is to do an extended full to full test by taking say a years (or other) mileage v the fuel consumed.
I often smile when the dash is telling me 32pmg and think we may have been put away a few years if we said our 3.5 trucks had done that ! 

As Micky says, just accept it and keep driving.
We came to motorhoming after many years of touring the continent by BMW motorbike, and although the bike achieved almost twice the MPG of the van, it worked out considerably more expensive when you added in the cost of several coffee/meal stops at commercial premises during the day.

Al.

All useful replies, thank you. Suspect it would give a worse rather than better figure in a brim-to-brim test, as people say dash figures tend to be optimistic. Maybe mine will improve too as the engine loosens up, as inspiredron says. Am also considering a remap at Celtic Tuning, who are local to me. They offer an “economy’ map as well as a “Stage 1”.

fortygreen wrote:Am also considering a remap at Celtic Tuning, who are local to me. They offer an “economy’ map as well as a “Stage 1”.

Beware that there might be an impact upon your insurance premium, which - combined with the cost of the remapping - would lengthen the payback mileage which you'd have to drive before breaking even. Failure to inform your insurer will, of course, potentially void the insurance cover because a remap - even a benign one - is a material factor affecting risk.

Cymro

Hi All

I have kept records of full tank to full tank since owning our Kemerton and have only achieved an average of 25.71mpg in 21000 miles with a best of 29.59mpg on a 400 mile trip to Scotland, motorway majority of the way, Bournemouth to Moffat. 
I think the components on the roof do not help, awning, air on unit aerial etc.

Yes it must be quite turbulent up on the roof garden. Though I doubt wind resistance is as big a factor at modest speeds as the sheer weight of the vehicle. Our old 2010 Symbol presented an even greater frontal area with its extra-high roof, yet showed 32-33 mpg on the dash. Maybe Euro 5 emission standards came at a cost of increased thirst over Euro 4 (2010 Symbol)? Still, it's looking as if my Kemerton consumption is fairly typical, and I'll just have to "get used to it". Thanks for all the comments folks.

We have a Euro 5 2015 Kingham (same engine), manual- with a huge sat dome on top. It’s 6.3m so same length. We average 32-33 (loaded) when trying. If less careful typically 27-29mph.
Today with a 50mph ave speed limit on a 20m journey got 37!!

However the killer is speed and weight so if travelling At 70 with full water and fuel it’s worse.

Wow, that’s much better, I’m envious. May I ask, is that the instrument reading or your own brim-to-brim calculation? How many miles are on the clock and have you owned your Kingham from new?

Yes, the readings are the trip computer ones. We have owned from new. 16,500 on clock. 

We used to own a tag axle, 8.6m 3l jtd and that had a trip computer showing 22-24 mpg so you should get better with your van!

With ford cars we have owned, when we checked the real consumption the trip computer over estimated by about 10%, but we have t bothered checking the van as it feels right.

So the difference is a puzzle. Maybe I should get the emissions equipment checked in case it isn't breathing properly, even though the van was serviced by the dealer when I bought it in October, and I asked them to do that specifically. 6,000 miles in 3 years suggests short journeys.

mikethebike wrote:I have studied fuel figures for many years.
 Despite knowing how to drive ,a mobilgas economy entrant,i cannot get anywhere near the high figures that owners on here say.
Its wind,hills and roundabouts that are the problem. However you need to do fuel checks over a full tank or so for a realistic figure.
Some of these more powful engines run rich.
Just accept it and keep driving. Micky

Mpg claims vary so widely i'm always sceptical, particularly of those in higher figures, and wonder at what 'science' they've employed to measure it. My method is crude basic and simple though i only do it when on tour. I 'neck' the filler as far up as i can, then run the van for 4-500 miles before 'necking' again. The van is driven according to roads, so part of my mileage may be on fast autobahn sections whilst other might be pottering along country roads or through towns....so it's a mix. I'm driving with full water tank and toilet. 

Whatever amount of litres it takes to 'neck' between each fill, then thats my mpg.

I also do the above when on a European tour. 
We usually head for mountains, either the Alps or Pyrenees.
The first tankful is UK motorway, over 30mpg.
The next is N or D roads in France, or the equivalent in other countries. I avoid all tolls, mainly because the drive is part of the trip, and nothing is more boring than continental motorways, this part usually comes out at 27 to 30mpg.
The mountainous part is mid 20's mpg.
Return repeat.
Over the last dozen tours the van averages 30mpg, never varies. 
I always run with a full fresh water and empty grey.
Al.