Transit MK7 average fuel calculations. (1 Viewer)

[Sandancers]

In the above vehicle would anyone know how the average fuel results are arrived at ?

It would seem to be a pretty simple calculation, count the number of injection pulses and measure distance travelled, a bit of maths and there you have your average fuel. And it should be pretty accurate. But is it ?

So, it is easy to count the injection pulses, but what provides the distance input ? I'm guessing some form of toothed cog sensor on a road wheel, anybody confirm that ?

Then we come to the calculation itself. I read a snippet somewhere that says the average fuel is calculated from the last press of the reset button as a continuous calculation. Like if you pressed reset on the day you bought it then 10 years later it would be showing you the average fuel consumed over those 10 years.

So why am I asking I hear you ask. Well, when I first got the MH brand new, on a Ford 2.2 140ps engine, weight 3t, it always showed an average fuel of 26.9 mpg. sometimes dipped a little under, but never above that. I thought that when the engine had done 10,000 miles I would see the average fuel increase. Nope, stayed the same.

But lately the reading has been all over the place. Bearing in mind I normally do 62mph on the motorways, the following is referring to motorway travel only. So sometimes the average shows 22.4mpg. I press the reset button and it will again show that reading over say 20 miles. I press reset again and the reading might show 24.7 mpg over the next 50 miles. Press again and it might show 26.9 for the next 50 miles. So I am wondering what might be affecting the average mileage so dramatically, bearing in mind I am doing the same speed on normal motorways, having the same weight and in the same weather conditions.

 

[gus-lopez]

No idea but I would be brimming it & refilling & comparing what that is accurately against the vans idea of consumption.

 

[andy63]

It would seem to be a pretty simple calculation, count the number of injection pulses and measure distance travelled, a bit of maths and there you have your average fuel. And it should be pretty accurate.

as the amount of fuel injected by an injector will vary depending on so many features on the engine map... time of pulse, boost pressure , fuel rail pressure, engine temp, eng load, throttle pedal sensor position how many injection pulses are triggered ie pre or post pulses etc etc... the wild swings or large variation could be caused by any number of things
im fairly certain from memory that the mk7 speedo and odometer get their info from the wheel abs sensors via their ecu..
Andy

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[suavecarve]

I m touching nearly 30 mpg off the dashboard and confirmed by rudimentary maths and not quite 6,000 miles yet (no motorbike in back on that trip (sic))

 

[Sandancers]

as the amount of fuel injected by an injector will vary depending on so many features on the engine map... time of pulse, boost pressure , fuel rail pressure, engine temp, eng load, throttle pedal sensor position how many injection pulses are triggered ie pre or post pulses etc etc... the wild swings or large variation could be caused by any number of things
im fairly certain from memory that the mk7 speedo and odometer get their info from the wheel abs sensors via their ecu..
Andy

I was intending to get it re-mapped next year so maybe that will solve the mystery.

 

[Reallyretired]

I am lazy so I go by the mpg figures given, though I know they're not particularly accurate. The fuel is going to cost me the same regardless of what the vehicle says. My car is set to reset the mpg every time I fill up don't think that's possible on the Transit.
Mpg varies enormously according to how much up and down on the road and a headwind can produce a big drop.

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[andy63]

I was intending to get it re-mapped next year so maybe that will solve the mystery.

well I had my mk 7 transit mapped a couple times and found it improved the drivability... the second mapping was to reduce the horsepower the first map was producing to a more sensible level , but more importantly to delete the egr function after I cleaned the intake side out of the excessive carbon deposits caused by the egr system. I left the egr valve in place to avoid any issues at mot time but disconnected its wiring harness...this was on a 2.4l engine and im not sure that the 2.2l ford engine has the same issues with the egr system...
my current vehicle, a landcover defender has the ford 2.2 l engine so I guess if I keep it long enough ill find out...

 

[The Wino]

We have I think the same MH and funnily enough ours was averaging 26.9 mpg as well for the first couple of years. It now seems to do a little better. Even in the days of roughly £2 a litre diesel it's a bit academic the cost of swapping to anything else is going to be most likely way more than the savings in fuel. Why are you getting a remap we find 140 BHP fine.

 

[Sandancers]

We have I think the same MH and funnily enough ours was averaging 26.9 mpg as well for the first couple of years. It now seems to do a little better. Even in the days of roughly £2 a litre diesel it's a bit academic the cost of swapping to anything else is going to be most likely way more than the savings in fuel. Why are you getting a remap we find 140 BHP fine.

A mildish remap should improve mpg and give a bit more power. So even if it costs £300 but I can get 10% better mpg I think it will be worth it.

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[The Wino]

A mildish remap should improve mpg and give a bit more power. So even if it costs £300 but I can get 10% better mpg I think it will be worth it.

If it's possible to remap that easily and without any maintenance issues why didn't ford when they made them?

 

[Sandancers]

If it's possible to remap that easily and without any maintenance issues why didn't ford when they made them?

Because Ford don't know where each vehicle will be used or how it will be used. Therefore they leave very wide parameters on the engine mapping so each vehicle will perform to a certain spec. However, by tweaking the parameters you can improve performance. Very much like Lewis Hamilton's mechanics adjusting his car's engines to suit each circuit.

 

[Stealaway]

A mildish remap should improve mpg and give a bit more power. So even if it costs £300 but I can get 10% better mpg I think it will be worth it.

I had a remap on my Ducato. Up to 160 hp. It made not one jot of difference to the MPG.
Waste of money really, it's a little smoother and makes overtaking tractors a bit easier but that's about all.
I wouldn't bother with it again.

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[abdn_alliance]

30mpgish

 

[L' Hobo]

No idea but I would be brimming it & refilling & comparing what that is accurately against the vans idea of consumption.

Sometime the old ways are the best! I personally just fill it up when it gets close to the halfway mark.

According to the dashboard thingy, I get about 30mpg despite traveling at the speed limit most of the time.