Thugzy

I've been tracking my fuel economy using fuelly App. I noticed how the average fuel consumption is off. It is wrong by showing 1L/100km less than actually calculated.... Not a big deal, just slightly annoying.

Anyone else notice this? Is this already known? All my previous vehicles (Benz, Honda, Mazda) have been 100% accurate

BlackBoost

Already known. Some are worse than others. Mine is pretty bang on. Changing tires to a different size will really screw it up.


To be honest, even hand calculating isn't 100% because your odometer and speedometer aren't 100% accurate either. Too many variables. You would need a GPS-based speedometer/odometer for better accuracy.


All you can really do is use your own calculations as a guide, and only compare to your previous trips to gauge if you're getting better or worse mileage as a guideline. Comparing to other people's results won't help you at all.

MaceWindu57

Just drive it; if you want fuel economy get a Prius.

iplayloudly

Mine is consistently off about 5%. I believe most others here are as well. For what its worth, my wife's Honda Pilot is also about 5% off.

twolastnames

Personally I think worrying about your exact mileage is a little silly, mostly because I'm going to guess it is way harder than people think. There was a Myth Busters episode comparing something with cars and mpg, probably a few actually. They always weighed the gas, not going by volume used. Why? Because temperature affects the volume of gas quite a bit. http://datagenetics.com/blog/april32015/index.html

Link goes into more detail. I'm going to go with unless you weigh your gas, your probably not as accrate as you think you are. Just use the trucks calculator to compare tanks of gas to each other as a troubleshooting means.

Eduskator

Do not rely on these piece of sh*t computers.

My truck's consumption calculator was dead on accurate for the first fuelup or 2. I remember how surprised I was. After that, things went bad.

My last trip meter showed a fuel consumption of 16L/100km (14.7MPG). After manual calculation, my real fuel consumption was 22L/100km (11.2MPG). 6L/100km of difference. That's insane!

I reset my trip meter at every fuelup to have an exact distance & put an equal quantity of fuel in the tank (I top it off, wait 10 seconds and re top it off.).

11screw50

Mine is off by some but it is inconsistent.

It is pretty close in the summer. It is off by more in the winter.

My theory has always been that it just doesn't account for the extra fuel that is used when the engine is cold.

Tvanpool

The milage calculated by the trucks computer is usually as accurate as calculating a single tank by hand. There are many variables that can impact accuracy when hand calculating mileage.
1. Accuracy of your odometer.
2. Accuracy of the fuel pump. (I feel sure you aren't getting more than you pay for).
3. Attitude of the truck when filling. ( a small difference in attitude can effect the amount of fuel you can get in the tank. And how can you be sure you are putting back exactly the amount you took out).

But like was stated above "I don't care what it is" as long as the engine is running properly and there is not a hole leaking fuel on the ground. My first new truck was a 1978 SC 460. Compared to that this new truck is great.

ThatNewWifeSmell

My gallons used is normally within 0.1-0.2 accuracy.

Ricktwuhk

Discussed many times. People often change tire size and don't change the computer so that's an issue. Or they use Remote Start, let it run for 15 minutes every morning, and it's way off.

I log the vehicle's readout and manually calc every fill on all my vehicles and the truck is within 0.5 to 1 mpg.