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Discussion Starter #1
As the proud owner of a new Venga 2, 1.4 CRDi, I felt the need to check out the fuel economy making use of the fancy trip computer. Reports in this forum and elsewhere claim that the trip computer is hopelessly inaccurate, that supermarket petrol is rubbish and reduces economy significantly and that cars generally and Kia in particular do not deliver the official economy figures viz.
Fuel Economy
(MPG)
Urban 54.3
Extra Urban
70.6
Combined 62.8
For those who don't have it, the trip computer records two trips A* & B* (either will do), Distance to empty (Range), average MPG*, instant MPG and elapsed time*. Items marked with an asterisk * can be re-set at any time.

So I have initiated a regime to reset the trip and average MPG at each fillup, and to record the relevant readings.Broadly my experience based on my first tankfull from Asda is that
1. The two trips and odometer are accurate and consistent as you might expect.
2. Distance to empty is based on a conservative MPG of 38.6 rather than the indicated average.
3. Average MPG deviates markedly, generally starts off low '-.--' or 15 to 20MPG rising to 60+ as the car warms up, and is unreliable.
4. Instant MPG, as expected, fluctuates a lot. At a steady motorway speed around 60-65 over the Xmas holiday due to heavy traffic, it varies around 60 - 80 MPG on the flat changing to around 30 to 40 'uphill' and 90+ 'downhill' on the motorway.
5. Elapsed time appears to spontaneously reset when the ignition is off for an hour or so. As a result it is totally unreliable.
My routine at each fillup is to record Odometer, Trip, Range and average MPG before fillup, then Range and fuel used from the pump. The following table lists three sets of results including fuel (remaining, used and tank capacity), Trip (miles since last refill), MPG, and Range (remaining, used and full tank).
The first column results labelled 'Actual' are considered to be accurate based on fuel as billed, tank capacity (48L) and trip miles (shown bold). The second column 'Indicated' gives the same results indicated by the trip computer based on average MPG, and Range before and after fillup. As the MPG figure varies it is considered to be unreliable. It read 53.5 at fillup but got up to 64 on the road a few minutes earlier. The final column 'Implied' uses the before and after Ranges along with the Kia's published tank capacity to calculate the same results. Litre/gallon conversion is 4.546

Actual Indicated
Implied
Fuel left 10.84 7.56 10.47
Fuel used 37.16 27.11 37.53
Fuel full 48.00 34.67 48.00
Trip 406.4 319.0 319.0
MPG 49.72 53.5 38.6
Range left 118.55 89 89
Range used 406.40 319 319
Range full 524.95 408 408

About 300 miles were motorway and the rest was short journeys in very cold conditions. Implied fuel based on Range and MPG = 408/48*4.546 is similar to the accurate figures so the fuel metering looks OK while the implied MPG is conservative, probably hard wired at 38.6. But how the trip computer derives its average MPG is anyone's guess. The manual says it is 'from the total fuel used and the distance since the last average consumption reset'.If that is so the reading should be more stable than it is.

Edited by: Derwentdale
 

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I've been having identical problems to the points you made below after doing similar checks to test the fuel consumption:


1. I agree with this point.


2. I'm not sure about this figure but I agree it gives a wildly inaccurate reading


3. Agreed. Mine [to use your words below] spontaneously resets to '-.--' sometimes when you switch on other times when you are driving along


4. Agreed


5. Agreed. It resets itself.


On top of these problems my fuel gauge is totally inaccurate, showing that the fuel tank has much more diesel in the tank than there actually is, with the result that I really don't have a clue how much fuel I've used because of the inaccuracies highlighted. It's been checked by the dealer and said to be working OK and that I should monitor the situation. I'll be booking it in again shortly because whatever they did didn't work.


I'm getting an overall 45mpg which is nowhere near the urban mpg, despite having done a few long journeys.


This is the 4th car I have had with a trip computer, one being a Kia Cee'd, and I've never had problems such as these with the trip computer, which have been very reliable and accurate. Again it's going back in again until they get brassed off with me taking it back.


It's very disappointing to buy a car where the basics don't work and the dealer can't solve the problem. If anyone asks me how the new car is going I tell them it's the next worse car I have ever had and they should think very hard before they buy one. All in all it's not fit for purpose and I shall be be writing to tell Kia if the dealer cannot solve the problems when I take it in.
 

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I think we have covered this issue with unrealistic fuel consumption figs that are actual and what is described as in theory to the stage it has been flogged to death. You get what you as an individual person can get. Everybody has a different driving style and is in NO way like what Kia get on a rolling road with no wind resistance and in a laboratory environment. So drive the car and enjoy it and stop worrying about trying to achieve the same results as kia or any other manufacturer.
 

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Discussion Starter #4
folkjokeopus,I had seen your earlier post re: inaccurate fuel gauge whilst collecting my numbers above. On reflection getting 9.64 galls into a 10.56 gall (48L) tank when the gauge reads 1/4 full is a bit worrying, especially when the computer shows 132 miles to fillup. 1/4 full implies about 12 L in the tank and not 0.92*4.546 = 4.2L and 132 miles implies 50MPG. Some of this discrepancy could be due to filling 'to the brim' including the fill pipe. Someonein this forum (not Venga I think) got an extra 5L in after the pump first cut out. Not sure where the 48L level is exactly, hence my attempt to make sense of it. But my experience is that petrol gauges are surprisingly accurate on level ground, especially when you consider how they work.

But it does seem that the Venga trip computer isn't working properly as the elapsed time and probably the average MPG reset spontaneously. If that is so then Kia need to know about it and do something to put it right.
 

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Discussion Starter #5
davy,Sorry if you find all this a bit boring but we economy geeks like to think we are getting what we paid for - fuel economy was an important factor in my choice of car. The money I handed over works OK so why shouldn't the car? Also I want to know how reliable the trip computer is so I don't inadvertently run out of fuel in the small hours miles from anywhere in foul weather. You get the picture.

Official car fuel consumption tests are supposed to be carefully performed according to EC directives to give realistic and most importantly comparable results -see VCACarFuelData.org.uk.It is unrealistic to expect them to compare accurately with any individuals experience, even over a tank full, as the conditions are likely to be incomparable.
But I don't think there is much in your point about wind resistance. I am not familiar with the testing details and the VCA don't say but wind and rolling resistance would have to be accurately modelled by the rolling road tests. They would appear, as in real life, as a reaction at the tyres.
 

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dont feel bad about raking over the coals as often as you like!! im besotted with the mpg on my soul and am constantly trying to improve it , as ive said before vw can build an engine and put it in a car and it gets what it says on the screen ,i know ive got one and it gave me 50 -55 mpg no matter what or how i drive , had i known the kia was going to be as poor as it is on fuel i wouldnt have bought it, as it isnt really able to do what i got it for without being thirsty, im going every where at 60 mph max to save fuel, what a joke ive not driven that slow on motorways for years ,yes it will do 80mph easily no doubt but will cripple you fuel consumption wise 70 mph isnt much better returning late thirties mpg wise thats all wrong in my book , should have given it a 6th gear ! sorry to be rambling on your venga site but just thought we(kia owners) are all suffering low figures that frankly dont even come close to what we were mislead into believing
 

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Hi all,


My understanding of the Urban/Extra Urban fuel consumption figures are that they are obtained on a rolling road. The car is at normal operating temperature and starts in neutral. The car is accelerated through the gears up to about 30mph at the manufacturers recommended gear change speeds. It continues at 30mph for 1.2Km then slows to a standstill with downward gear shifts, then it is turned off. The fuelconsumption is then measured for thetotal test and aconsumption rate calculated. Extra urban is a similar test carried out ata final speed of 60mph.



Quite honestly, it does not seem relevant in the real world. I personally have not been able to deduce any correlation between the two consumption figures and the combined figure although there must be one.



I believe that wind resistance increases by the third power as the speed increases and hence the rapidly increasing consumption as speed goes up. My guess is that the manufacurersprogramme their cars to give good test results because thats what we, the public, look at.



I looked at most small diesel car consumption figures before I bought the Venga. The Fiesta looks brilliant on paper along with the Polo. Note that the Hyundai ix20 engine turns in different figures to the Venga although the engine looks the same. Kia had two different sets of figures for the Venga in their website specifications until recently and when I pointed it out to them they said that the figures (the better ones, identical to the ix20) were for a new engine yet to be released. In the end I was so confused by all the different numbers that I gave up and bought the car that I liked the best....and had the longest warranty.



Drive, and enjoy!!



Bob
 

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I've got a Rio diesel and I'm not impressed with the fuel economy. I drive almost exclusively on the motorway at a constant 70mph and yet I only get between 50 and 52 mpg. The constant 75 mph figure for the Rio is 69 mpg. I wasn't expecting to get that, but was hoping I'd be getting at least high 50s.My old car had an official mpg of 34 at a constant 75mph and if I drove it at a constant 70, I would get 35 mpg. the odd thing is I could increase my fuel economy in that car by 50% when going at a steady 56 mph, whereas in the Rio you only see a very slight increase in mpg at lower speeds.


It's annoying as a friend of mine has a 12 year old VW SPAM and despite its age it has no trouble getting well over 50 mpg.



In terms of filling the tank, I can easily get 5 litres into it after the pump cuts off. My record is about 8 litres!
 

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I have completed 1188 miles on myKia Venga 2 1.4CRDI (Demonstrator with 2000 miles on it) since purchased Nov 2010 with average 47.27 mpg, on mainly short local journeys. This is less than I had hoped for but it is totally unrealistic to expect manufacturer's publishedUrban/Extra Urban fuel consumption figures - that applies to all manufacturers. Overall, I think the Venga is an excellent car - even my wife enjoys driving it! I ignore the inaccurate mpg, etc from the computer trip meter as I keep my own purchase record for all fuel purchased - my records go back to 1991!
 

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I have had my Venga 2 1.4 CRDI 3 weeks covering 1200 miles. So far I am averaging 58mpg mainly on long runs 30 miles each way a third of which is on the motorway so reasonably pleased. Have to calculate with a receipt and a calculator as computer resets itself three times a week for no reason. ISG does not work which boasts a saving of 10-12% in the brochure.
 

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Hi all,


For anyone interested, I recently "brimmed"the tank on my 1.4 diesel.With the fuel gauge reading full, I managed to get another 18 litres of fuel in the tank. It had to be done very slowly because the filler was continually foaming back and cutting the pump off. ( no queue behind me at the pumps. ) I didn't manage to actually see liquid diesel, but it must have been close. Ithen completed 217 miles before the fuel gauge came off the top stop and all this time, the " miles to go before fill up" reading remained at around 380 miles.



I am getting around 60mpg as indicated by the trip computer but nothing like this figure when I work out the consumption using fuel purchased and miles run. Thats what prompted me to try and "brim" the tank, because I thought I was putting more fuel in each time, and getting a poor consumption figure ( around 50mpg ) as a result.



I suppose the point I am making is that there is a large range (18litres) between full, very full, and abso-flippin-lutely full.
I reckon it will be several fill-ups before I am able to work out the real fuel consumption but already it is looking better, more like 55mpg.



Bob



P.S. Elsewhere on this forum, people have warned of the dangers of brimming the tank, possibly resulting in diesel escaping round bends, and ending up on the road. This is a nightmare for bikers, of which I am one, and 19% of all motorcycle crashes are on spilt diesel. So it isn't something I will make a habit of. B.
 

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Discussion Starter #13
To get a consistent fill, I push the nozzle in all the way and pump until it cuts off. My actual MPG is now around 56 which I see as pretty good as it includes a high proportion of urban driving. But I have yet to get the trip computer fixed, so the 'average MPG' regularly re-sets on its own.I regularly get around 60 miles before the 'miles to go' varies significantly from its 'full' value of around 405 miles. I also check the total trip (since filling) + miles to go, which rises from an initial 405 to around 535 before I am ready to fill again with an indicated 80-90 miles to go. I reckon the miles to go is based on the metered fuel left in the tank (which tops out before you begin filling the delivery pipe) and an assumed MPG of around 39, less than my actual.
Bob seems to be getting 217 miles for around 18 litres (around 55MPG) which aligns very well with his results and with my experience.
 

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i have had a venga diesel for 5 weeks, and the fuel consumption is erratic.
filled up from new, recording mileage anf fuel.
filled up 2 weeks later, worked out at 48mpg.
filled up on saturday to go to carlisle, that worked out at less than 40mpg.
came back from carlisle, mainly motorway driving, filled up again, got 45.5 mpg.
i know the figures quoted in the brochure are as a guide,
but the mpg appears to be both erratic and low.
any advice or information would be appreciated.
robin.
 

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Robin


Don't expect any more mpg. After nearly 4000 miles over half of which is on long journeys I'm averaging an overall 45mpg in my Venga 1.4 Eco CRDi. On town driving it's doing an average of 35mpg!



I realise that the published figures are not realistic - but the figures for the Venga are a joke.



I'm still waiting for a result on my trip computer which has a mind of it's own - it constantly resets to 0mpg and the miles to go reading is wildly inaccurate - the dealer is reluctant to change it as Kia have not got any faults recorded for it. The fuel gauge always shows full however much petrol is in the tank.



All in all the Venga is a crap car which I am looking to get rid of as quickly as possible.



David
 

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Hi David,


Sorry to hear of your bad experiences. The resetting mpg is a known problem and a fix is definitely available. I am getting at least 55mpg mixed driving and yesterday came back from Letchworth to Market Rasen recording 63mpg, along the A1 and A46. In town, the average mpg holds up well and rarely falls by more than 0.2 mpg, usually around 57mpg. I bought the car for the economy so I drive it in a way to get the best out of it. I love mine, and wouldn't change it.



Good luck



Bob
 

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I agree with you that the isg does nt make any difference to economy,its merely there for 2 reasons,thefirst for those who sit in traffic for hours with the engine running,where as no one with an idea of how an engine, or pdf filter operates or an interest in saving fuel.
the other is merely to make the venga fit in to the £30 year road tox bracket which is a popular sales bracket to be in at the moment, and anyway, my isg fails to start the car up again half the time.Just a gimmick.

James.
 

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Before my mpg reset itself I had got it up to 50 with some pretty average driving really, not really trying to get it up at all. I have filled up (18 litre's, don't know what gradefuel was in it before)andput about a litre more in after first clickoff of Shell super diesel and am driving up to Durham tomorrow. I have reset the odometer at the garage and will fill it up as soon as I get there, work out the mpg manually and compare it with the indicated, and post it on here. I too, am besotted with MPG. My old Patriot easily managed its claimed 42mpg so I will be slightly annoyed if I can't get over 65 mpg easily on a long motorway trip!
 

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Hi jonno,


the best I have managed is 63mpg on a long motorway trip and I have found that the speed at which you cruise is very critical. IfI set the speedo on 70mph and maintain that, I can get around 58mpg, but if I drop to 65mph, the fuel consumption improves to 63mpg. Headwinds are a killer! Supermarket fuel loses meat least3mpg all round.



Bob
 

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Hi Bob,yes i too have found supermarket fuel a bit less efficient.And yes,the venga really does nt like headwinds,or sidewinds.
James.
 
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