Easiest Way To Keep Track Of MPG?

Today I did a little reading and looked into the logging function of my OBD Fusion app. The app keeps logs every time you connect to the bluetooth OBD dongle. Up till now my app with default settings logged my longitude, latitude, and vehicle speed at a rate of one data point per second and created a CSV file.

After reading and playing looking into the available settings I have a better understanding of where the Total Fuel Economy number is coming from. I started using the app pretty regularly on August 31, 2025 and I have data from every drive on my phone for longitude, latitude, and vehicle speed in a CSV file. I am under the impression that there is some data that the app stores that is not outputted into a CSV file and that is where it is getting my Total Fuel Economy that does not reset with the trip odometer.

I have changed the settings to log all the PIDs. I believe this will give me all the data of the PIDs I have selected to be displayed in the app in a CSV file. So in addition to longitude, latitude, and vehicle speed I am expecting to see data logged from hybrid battery power, trip duration, engine power, vehicle speed, gps speed, trip distance all saved into the CSV log file.

In summary using an OBD dongle with OBD fusion should provide a method of tracking fuel economy in addition to a lot of other data for each drive I take and connect to the OBD dongle. I can than open those CSV log file in either Numbers, Google Sheets or Excel.

I will double check this is correct on my next drive later today. Until then here is a screenshot that gives an idea of the logging preferences available in the app.

 

MPG is still calculated the same way i.e. distance traveled over gallons of gas consumed. It just doesn't give you a complete picture or an accurate way to determine how much you paid to travel each mile.

With tracking in the app I am expecting to get a clearer picture of total cost. I don't have any immediate plans to use the data more then just experimenting out of curiosity. I can now track battery pack charge as well as fuel consumption in one log file so when I want to see the relative price for traveling by using gas versus electricity I now can more easily than I could using my previous methods.

My main method previously was taking pictures of the odometer, percent charge, and fuel gauge.

I also like being able to see a live snapshot of the contribution of power of each system(gas vs. electric), how changing the drive settings (eg. eco, normal, sport) and how using the built in GPS and Predictive Efficient Drive alter each systems contributions.

 

After returning from some errands I checked my phone and the app. The logging worked. Here is a screenshot of the CSV file it generated with the 13 additional data fields I selected.



I also didn't realize that the app was actually logging each trip. Here is a screenshot of my two short trips today.





In summary the app both logs data to view in the app and data in the form of a CSV file which can more easily be exported. That are settings for each.

I think that is "Scan ECUs" for diagnostic error codes. OBD Fusion has that too but my understanding is that it is a pretty limited scan in these type of apps without much if any ability to reset or edit ECU data like you can in more robust OBD tools used in professional shops.