Absent a working gas gauge, you could keep a log book, tracking the amount of gas you have put into the car. This is a good deal trickier because you must also take into account the average miles per gallon your car gives, the proportion of city vs. highway driving, and many other factors that may affect your car's mileage. You are more likely to unwittingly run out of gas by using the log-book method of accounting than by consulting your on-line, real-time gas gauge.
On This PageDecember 1989, No. 28
There are a number of ways to keep account of the gas in your car. The best way is to consult the gas gauge. It will tell you how much gas you have, and how much gas you have used since the last fill-up.
S&Ls: Running on Empty
Last Updated: 12/29/89