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Discussion Starter #1
Did a short trip home from work today ( 7.5 miles) and reset cars trip before I set off. When I got home the MPG on trip computer read 36 MPG, but the MyPeugeot app said it was 50.3 MPG. I would've thought that both values would be roughly the same?
 

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7.5 miles is nowhere near enough to get a reliable MPG figure. It needs to use a few gallons not 0.2 of a gallon. Over time the reading will get close to a real world number. Worrying about a discrepancy on such a short journey is pointless. As for the discrepancy - who's to say the formula in the app is the same as the formula in the trip computer ?
 

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The trip computer is measuring the actual amount of fuel injected so ought to be more accurate. The App probably doesn't take into account the high fuel consumption of a cold engine.
 

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Discussion Starter #4
7.5 miles is nowhere near enough to get a reliable MPG figure. It needs to use a few gallons not 0.2 of a gallon. Over time the reading will get close to a real world number. Worrying about a discrepancy on such a short journey is pointless. As for the discrepancy - who's to say the formula in the app is the same as the formula in the trip computer ?
I'm not worrying storeman simply wondering. I'm not looking for a complete MPG evaluation of the car, I'm just after the MPG of a particular journey and 7 miles is fine for that. As for the formula's been different there is onIy one- miles done divided by fuel used.
I'm off on a 150 mile round trip on Sunday so it'll be interesting to see if the app gets its figure closer to the cars.
 

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Cold starts, all braking and particularly acceleration from rest, kills a short journey figure.
9999 on the trip meter will give you the truth but that takes patience.
 

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As for the formula's been different there is onIy one- miles done divided by fuel used.
If they give different values, they self-evidently are using different data. My guess is that the app is using data averaged over a longer time period. It shouldn't do that if you operated the app correctly, so if that's the case it's probably a coding fault.
 

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Discussion Starter #7
As for the formula's been different there is onIy one- miles done divided by fuel used.
If they give different values, they self-evidently are using different data. My guess is that the app is using data averaged over a longer time period. It shouldn't do that if you operated the app correctly, so if that's the case it's probably a coding fault.
I agree that the app has to be using different data, but as it gets the data from the car I don't know why that is. The app varies a lot with the MPG data where as the car is more consistent, so I guess it's a problem with the app.
 

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I'm not worrying storeman simply wondering. I'm not looking for a complete MPG evaluation of the car, I'm just after the MPG of a particular journey and 7 miles is fine for that. As for the formula's been different there is onIy one- miles done divided by fuel used.
I'm off on a 150 mile round trip on Sunday so it'll be interesting to see if the app gets its figure closer to the cars.
It's not as simple as miles divided by fuel used - the app has no way of knowing how much fuel is being delivered to each cylinder so has to have some kind of formula to guestimate the fuel being burned by the engine.

Also as someone else has pointed out, the fuel consumption will change as the engine warms up but also the app has no way of knowing the extra strain on the powertrain when driving uphill or when the injectors shut off going downhill meaning the app will use a programmed fornula wheareas the onboard trip will use the data from the roadwheels and the amount of fuel delivered to each injector everytime they operate.

Still - if 7 miles is accurate enough for you then that's fine.
 

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Discussion Starter #9
Storeman- at the end of any trip your car sends data to the MYPEUGEOT app - which includes FUEL CONSUMPTION amongst other things. So when the journey has finished and you turn your engine off, the car sends the fuel consumption figure to the app- so when it's warming up or using extra fuel will be taken into account. I don't know why the figures on my trip and the app are sometimes so different and by the looks of things neither do you. I guess it's not that important anyway but a big thanks to you for all your help on the matter :):)
 
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