Fuel consumption - 2015 2.8 litre diesel

[Jprad]

Hi Doug I'll give 40psi a try, drive slowly and update the consumption I get. 

 

[Geoff_C]

I will check my tire pressures too, and on the next tankful make sure I am also at 40psi.  However I thought I should probably show an image of the "fuel consumption" that I use, as there are 3 such on the Prado. One is shown above, the Eco App bar chart, and two are on the dash. I always have my dash set to this setting. Now as I had to take the photo while stationary, the horizontal bar with the eco range markings is missing. I ALWAYS drive with ECO on, and try to keep inside the "ECO" range. But this figure of 10.6 is virtually unchanged in 6000 km. The only other figure I saw here was 10.5 after 400 km of motorway driving. I also have TWO GPS on my car, and never use the speed reading, as its inaccurate. MY GPS speed reading never vary from each other by more than 1 km/hr

[JohnLynn]

You guys have me quite worried about tyre pressures now, I must admit that my pressures haven't been checked as much as recommended in the handbook. Also the plate on the door and the owners manual recommends 200 Kpa which is 2.0 bar or 29 psi this is both for loaded and light vehicle use and for both sizes (245 and 265) of 17 inch rims.

I am not going to post what my pressures were, as I don't trust Toyota to not monitor this forum and cancel my warranty ! but they were lower than recommended.

I have taken a couple of pictures of my average consumption as shown above, and also the range. I had covered about 50 Km since filling up. I have reset the trips and will work out exactly the next time I buy some fuel.

  My photography skills are not good so I hope you can read the figures.

[cudestir]

You should be running 265 65 17 at between 36 and 42 PSI dependent on the load. I have fitted the scangauge to my car today and its shown some very interesting figures. Now bare in mind I was using this on my 4l v6 for many years and found vary accurate.

City traffic fairly free flowing I got 7.6l/100km over about 60km. When cruising at 100km/h on the freeway I got 5.2l/100km and when doing 60km/h I got 4l/100km. Crazy I know but I will be able to confirm these figures after a few fill ups have been complete. I haven't really decided to use the Toyota's gauges prefer the scangauge as I can confirm that is real. 

[Geoff_C]

18 hours ago, cudestir said:

 I have fitted the scangauge to my car today and its shown some very interesting figures. Now bare in mind I was using this on my 4l v6 for many years and found vary accurate.

City traffic fairly free flowing I got 7.6l/100km over about 60km. When cruising at 100km/h on the freeway I got 5.2l/100km and when doing 60km/h I got 4l/100km. Crazy I know but I will be able to confirm these figures after a few fill ups have been complete. I haven't really decided to use the Toyota's gauges prefer the scangauge as I can confirm that is real. 

 Hi Cudestir,

Can you give me either some info or a link to "scan gauge" so I can get one of these.  Because my average fuel reading is not usable, as i will explain below. I guess when you say "cruising" at 100, you mean on the speedo, because its not accurate. I have two GPS in my car, and thats what i use all the time.

I just looked up the Toyota Press release for my vehicle:
 

Quote

Now, Toyota Australia has revealed that the ‘Global Diesel’ (GD, or more formally 1GD-FTV) 2.8-litre engine is being brought to market in the Prado from August, boasting 450Nm (auto, 420Nm for the manual) and 130kW. Toyota has also announced that the Euro 5-compliant engine will be coupled to either a six-speed manual or a six-speed automatic transmission, the combination yielding significantly improved combined-cycle fuel consumption of 7.9L/100km (manual) or 8.0L/100km (auto). According to the car company, the fuel economy gain is 10 per cent for the manual, 5.9 per cent for the auto.

I have just completed my second tank refill against a measured trip distance. For much of this tank I was really trying to save fuel. I achieved 10.71l/100 against the previous tank which was 11.1l/100. Now to the interesting thing. I did not use the full tank, so my distance was 612 km, but at NO TIME during these 600km did the average fuel consumption shown on the dash change from 10.6. In other words, I achieved a fuel consumption change of of 0.6l/100 yet the reading did not change, although it should now be closer to 10.0. In fact in 6000 km it has never varied by more than 0.1 - only 10.5 and 10.6 have been shown on the dash. It would appear that my vehicle is well over the advertised fuel consumption figure of 8.0 for an auto. I would personally be happy with 9.0, but some owners tell me they have seen 7.5.

I checked my tires with a very accurate gauge, and cold. They are 36 psi. I will pump them up to 40 and see if there is any change. I will have to take my car in for service next week, but I am not expecting any sympathy from the dealer. But they may change the tyre pressures if they think 40 is too high. 

Geoff

Edited March 3, 2016 by Geoff_C

[cudestir]

If you take a look at http://scangauge.com.au/ they are in Queensland and very helpful. I have attached a pic of my fuel use today. This was for about a 20 min drive through heavy traffic

 

 

[JohnLynn]

I hear what you say about tyre pressures, infact there are several comments about this subject on the Prado forum. When my wife gets back with it I will increase mine and post the results.

Must admit I am a bit confused about the scangauge being more accurate than the vehicle as surely both get their source of information from the same canbus? I presume there are many ways of reading this like a BT adapter from the OBD2 socket to an app on a mobile phone for instance?

[cudestir]

Yep it uses the OBD2 port. My VX has a different display to the GXL and I can reset the ave fuel usage and get new values which are kind of accurate. My instant fuel usage is a bar that increases and decreases. See pic

[Geoff_C]

2 hours ago, cudestir said:

Yep it uses the OBD2 port. My VX has a different display to the GXL and I can reset the ave fuel usage and get new values which are kind of accurate. My instant fuel usage is a bar that increases and decreases. See pic

 

My son recommended I zeroise the average fuel usage reading, and I have. Then I suddenly came to the conclusion that my reading of 10.6 did not change, because it is an average of 6000 km. Woah!!! So its not an as you go average, which every other car I have had in the last ten years has had. Geez!! How stupid is that? Even the eco app does not give an average, although its continuous using one to calculate the range. THATS the figure I need.

Thanks for that link, I will get that item.

Geoff

Edited March 3, 2016 by Geoff_C

[Hiro]

12 hours ago, Geoff_C said:

My son recommended I zeroise the average fuel usage reading, and I have. Then I suddenly came to the conclusion that my reading of 10.6 did not change, because it is an average of 6000 km. Woah!!! So its not an as you go average, which every other car I have had in the last ten years has had. Geez!! How stupid is that? Even the eco app does not give an average, although its continuous using one to calculate the range. THATS the figure I need.

Thanks for that link, I will get that item.

Geoff

Maybe because that's how average fuel consumption works - all the cars I've driven (not just Toyota) with average fuel readings have to be reset if you want them to start afresh, they're not a short-distance rolling average of the last say 100km, or the current tank of fuel...

[Geoff_C]

30 minutes ago, Hiro said:

Maybe because that's how average fuel consumption works - all the cars I've driven (not just Toyota) with average fuel readings have to be reset if you want them to start afresh, they're not a short-distance rolling average of the last say 100km, or the current tank of fuel...

Well I cant guess what cars you have owned/driven, but I currently have a Porsche, previously had a Merc and before that a VW Eos. All of them had a short-term fuel usage figure shown on the dash that was responsive enough to reflect your current driving style. Sort of what you would get off the ECO bar chart if it actually showed one figure for the entire display. But if this is how it works, I know what to do to get what I want out of it. 

[Hiro]

3 hours ago, Geoff_C said:

Well I cant guess what cars you have owned/driven, but I currently have a Porsche, previously had a Merc and before that a VW Eos. All of them had a short-term fuel usage figure shown on the dash that was responsive enough to reflect your current driving style. Sort of what you would get off the ECO bar chart if it actually showed one figure for the entire display. But if this is how it works, I know what to do to get what I want out of it. 

That's normally displayed as an "instantaneous" fuel consumption figure.  Most trip computers Ive seen will have both (instantaneous is really only useful at cruise or long periods of heavy throttle like hills, in city traffic it just bounces from heaps to none and back again)

I've mostly driven Jap/RoK and Aus cars (Toyota, Mitsi, Nissan, Hyundai, Ford/Holden etc), the only Euro that I've spent more than 5 minutes behind the wheel is an AH Astra which was pretty pov-pack (didn't even have a temp gauge)

[Geoff_C]

2 hours ago, Hiro said:

That's normally displayed as an "instantaneous" fuel consumption figure.  Most trip computers Ive seen will have both (instantaneous is really only useful at cruise or long periods of heavy throttle like hills, in city traffic it just bounces from heaps to none and back again)

No that is not what I mean, and not what they (Euro cars) display. There is a technique called exponential smoothing, and if you feed an instantaneous consumption figure into it, depending on the value of the smoothing constant in the formula, you either get a very responsive "average" or a slowly changing "average". And that is what Euro cars all display, well the ones I owned, and I assumed it was what I was looking at. It is a very usable meaningful figure. You never have to reset it, it just works. The Prado also has an instantaneous figure that can be shown on the dash, but its of almost no use, as you pointed out, because it is well, too responsive. And of course over the first several hundred kms of my new Prado the straight average was ok, but over 6000 km, its no wonder it did not change. As I got more and more annoyed. 

[Jprad]

My fuel consumption screen ("after refuel") has been reading 11.8 for ages. Doesn't seem to change much. Seems heavily damped, I remember it changing 0.1 occasionally after a very long drive. I am looking more at the responsive "average" fuel consumption and can reset this before a drive. It's a challenge to keep this from fluctuating but I can get it to read 11.2-12.5 L/100km in the city with very careful driving and aircond on.  If I even try to keep up with other traffic eg camrys, volkwagens, corollas etc then it is up to 13-15L/100km.

JohnLynn is getting a decent display of 9.2L/100km and range of 1460km. This sort of economy and range I've never seen in light city driving.

Anyone else getting this kind of range? Assuming I go for a long highway drive and my average fuel consumption falls from 11.4L/100km down 22% to 9.2L/100km I am hoping the range should recalculate and redisplay on the trip computer as 1450km? 

I am finding 40psi a bit harsh on rough roads, I'm trying 38psi for now.

 

Edited March 6, 2016 by Jprad
Wrong photo

[Geoff_C]

On 5 March 2016 at 1:39 PM, Jprad said:

My fuel consumption screen ("after refuel") has been reading 11.8 for ages. Doesn't seem to change much. Seems heavily damped, I remember it changing 0.1 occasionally after a very long drive. I am looking more at the responsive "average" fuel consumption and can reset this before a drive. It's a challenge to keep this from fluctuating but I can get it to read 11.2-12.5 L/100km in the city with very careful driving and aircond on.  If I even try to keep up with other traffic eg camrys, volkwagens, corollas etc then it is up to 13-15L/100km.

 

It took me six months to realise the dashboard fuel consumption average is an average since last zeroed, and in my case that was 6000 km, so it was not changing at all and was 10.6.

However this weekend I drove 35 km from the Northern Beaches to Breakfast Point, in heavy Friday afternoon traffic, but driving as carefully as possible and got 12.6 average for that trip only. I had a short freeway drive today, maybe 5 to 10 km, and with the reading reset at the beginning of the freeway, saw that when driving at a steady state at around 80km/h it is around 7l/100 or even slightly under. That is the very first time I have had that sort of insight. Then returning the 35 km this afternoon, with much less traffic and in this case going basically downhill, I got 8.2 l/100 for that trip. So the difference of traffic plus some "uphill" driving gave 12.6. I can now see how my average of 10.6 for 6000 km came about. But its a world of a difference from the Toyota claim of 8l/100 for the city cycle. I still have not increased my tyre pressure from 36.

[Jprad]

Hi Geoff_C,

Yes it looks like it needs to be zeroed to be meaningful. Those figures are close to what I am getting. I get better figures if the aircond is off . It's still not close to the  official claim of 8/100! I did ask my local mechanic and his opinion is that the ADR figures tend to be BS.

I'm still not sold on the range which is repeatedly displaying about 1200km on a full tank.

[Geoff_C]

I have a theory that with the smaller 2.8l motor, this vehicle may be economical on the flat, but give it a hill and its game over? I have a lot of hills around my home, and maybe thats why I cant get a lower fuel figure? 

[Jprad]

2 hours ago, Geoff_C said:

I have a theory that with the smaller 2.8l motor, this vehicle may be economical on the flat, but give it a hill and its game over? I have a lot of hills around my home, and maybe thats why I cant get a lower fuel figure? 

I noticed driving in the south eg around Hurstville region where it is hilly the car drinks a lot more than in the inner west where there aren't many hills. I think your theory is most likely correct.

 

 

[cudestir]

I am seeing 12 to 14l/100km when driving up hills. I have just done my first refill and noticed that the trip computer is saying I had 8km left. When I filled it I could only get 133l in. That means its out by about 8.8% which is significant. I still had approximately 200km left of driving before it really was empty. I will report back my fuel usage each refill which will most likely be every 2 to 3 weeks. 

[Jprad]

18 hours ago, cudestir said:

I am seeing 12 to 14l/100km when driving up hills. I have just done my first refill and noticed that the trip computer is saying I had 8km left. When I filled it I could only get 133l in. That means its out by about 8.8% which is significant. I still had approximately 200km left of driving before it really was empty. I will report back my fuel usage each refill which will most likely be every 2 to 3 weeks. 

Appears like there is fuel left in reserve after "empty". Others say it needs to be filled slowly so the fuel doesn't foam to get the full tank in?

Yes the Prado seems quite thirsty up hills!

[Jprad]

Most recent consumption figure for a full tank averaged at 11.6l/100km from fuel receipt, mostly city driving (probably 90% city) and one trip to Blue mountains and back to Sydney. Tyre pressure 38psi, usually two people in car and usually very conservative driving. Aircond front and back on. Total range achieved was about 1160 km before fuel light came on. Filled 132l. The Toyota "average" fuel consumption showed 11.2 and the Toyota "after refuel" showed 11.8l/100km.

I finally figured out how to get the stubborn "after refuel" consumption readout to change and reset:

• the low fuel light has to be on ( the tank has to be "empty") 
• the tank then has to be filled full to the brim
• the fuel consumption read outs needs to be zeroed at the petrol station straight after filling

After I did this the "after refuel" readout which was usually stuck to 11.8 went up to 30.0 then fluctuated wildly and so far settled at 12.4l/100km city driving. Will see how this new tank goes as I've put in a bottle of injector cleaner.

Another thought, what could contribute to a higher than expected fuel consumption in some new Prados?

• poor quality diesel?
• wheel alignment issues?
• Slight vehicle mechanical build differences?
• transmission slipping more than it should?
• Different breaking in approaches with different owners?

Happy Easter!

Edited March 19, 2016 by Jprad

[Geoff_C]

Well those figures are not dissimilar to mine. Its very seriously affected by both hills and traffic. Get a flat road, steady speed its pretty good on consumption. However I did not have to go to all the trouble you did after re-fueling for the range to reset on the bar chart in the App. It did not reset immediately, leading me to conclude it only recalculates about every 3 to 5 minutes, but it did recalculate automatically. But if you are talking about the average consumption figure displayed on the dash with the bar of whether you are in "eco" range or not, that will reset any time on my car, even while driving, by just holding the selector button down for a second or two. It will fluctuate wildly initially because its an average since you zeroed it, which is why after 5000 km mine never changed. So I have no issue with needing the low fuel indicator to be on, and I have never seen it anyway, as I typically refuel at about 60 to 70 litres used. I don't see the point in having a long range tank that is empty. 

My vehicle has only done 6000 km, and I concede it may improve as the engine loosens up. 

[Jprad]

Hi Geoff,

my Prado has three things showing average consumption: The App graph, the dash average(with a current consumption gauge) and a seperate "after refuel" dash average. The "after refuel" on my Prado doesn't zero on demand. Maybe it's a Kakadu thing?

I am about to hit 5000km so hopefully it loosens up.

I am now averaging about 12L/100km in the City as I got tired of crawling slowly from traffic lights. I would say with my driving style 11.5-12L/100km would be the norm for driving in Sydney, usually with Aircond on, driving conservatively but not extremely slowly, with a range of 1150km before fuel light.

One thing I did notice is the consumption doesn't seem affected by load much. It doesn't matter if there is one person in the car or seven, consumption doesn't change much. But yes, hills increase consumption.

 

 

 

 

 

[Geoff_C]

16 hours ago, Jprad said:

Hi Geoff,

 and a seperate "after refuel" dash average. The "after refuel" on my Prado doesn't zero on demand. Maybe it's a Kakadu thing?

 

 

 

 

Hi Jprad,

 

It might be a Prado thing, or even simply that you have a newer release of the software. But mine is a dynamic instant reading, and really not much use at all.

Geoff

[JohnLynn]

My long term average reading has dropped to 8.9, this was reset 2.5 tanks ago and consists of varied journeys including a small amount of towing.

I opted for a manual because I wanted to control what gear to be in, not Toyota's software although I am aware that I could do this with an auto.

I do not know how the modern Prado automatic gearbox box works, does it use an oil  torque converter? if so I am convinced that these are inefficient. Each time they slip including being stationary in drive they are wasting energy in the form of heating the oil.

I did not believe the consumption figures quoted in the sales blurb quoting the auto to only be 0.1 L/100Km worse than the manual.

I know that manual versions are rare in Australia and am waiting for the flack for suggesting this!