Do you measure fuel consumption at every fill? Glance occasionally at the driver computer readout to see how many litres of gas per 100 kilometres your engine has sucked out of the tank?
The driver computer display is often inaccurate – sometimes by more than 15 per cent. Some are precise. Most can’t be trusted.
Measuring mileage manually is easy: After your next fill up, reset the trip meter to zero.
At the following fill, two numbers are required. The first is the number of litres of gasoline dispensed, decimal removed, and rounded to four digits. The second number is the readout on the trip meter.
So, for example, you put 47.221 litres of unleaded into the vehicle, and the trip meter says 483.2 kilometres. Bust open your calculator app and divide 4,722 by 483.2.
Congratulations! You achieved 9.8 litres/100 km. Reset the trip meter to repeat the process for your next tank.
Tracking fuel mileage accurately is a habit that can reveal a practice that’s costing or saving you money, and may even expose a steady increase in consumption that points to a problem with your ride.
“We see a lot of customers complain of poor mileage when they visit,” says Paul Kennaley, a Sudbury, Ont., mechanic. “Plugged filters, worn spark plugs, and even tire pressure and tire wear are the usual suspects.
“But these things tend to increase fuel consumption slowly, so drivers don’t notice until it gets really, really bad. Usually, a simple check-up and tune-up can improve fuel economy on a vehicle with a few issues like these.”
Ryan Peterson, manager of automotive services with CAA South Central Ontario, adds that “often a decrease in fuel economy is a symptom of a mechanical problem. Drivers should book vehicle inspections in the spring and fall, replace air filters as recommended by the manufacturer and have their engine tuned regularly to improve fuel efficiency.”
Some easy maintenance tips can combat poor fuel mileage in a big way, as well as increasing the peace of mind that comes from knowing your ride is in tip-top shape.
Tire pressure: Improperly inflated tires can cause your ride to burn more gas, and they wear out faster. Thankfully, checking and adjusting tire pressure only takes about two minutes, after an investment of about $4 for a tire-pressure gauge.
“CAA recommends checking your tire pressure monthly, first thing in the morning, before the car has been driven, and when the tires are cold,” says Peterson.
Checking pressures regularly helps maintain good mileage, especially when temperatures fluctuate widely in seasonal transition months such as November and March. Your owner’s manual has the scoop on tire pressure requirements, and checks should be carried out, even if your ride has a tire pressure monitoring system (TPMS).
“The electronic tire pressure monitoring system is designed to provide real-time information and warn drivers about under-inflated tires,” says Peterson. “It is not meant as a replacement for manual air pressure checks.”
Engine air filter: Chances are, your engine air filter has sucked up a whack of pollen, dirt and insect life over the spring, summer and fall. Winter will see plenty of dust and sand colonizing the filter, too.
A plugged air filter puts the engine in a choke-hold and causes it to use more fuel to compensate for the lack of airflow. Lousy performance and even burning oil are other side effects. Many air filters can be changed for about $20, in five minutes, with simple hand tools.
“We’ve seen customers who have literally never changed their filters,” says Kennaley. “In our climate, drivers are best to stick to the severe maintenance schedule for air filter replacement. I see air filters weekly that are plugged so badly, it’s a wonder the engine even ran. In cases like this, a clean filter, quite literally, cuts fuel consumption by a third or more.”
Fluids: A fresh oil change, as well as new transmission and differential fluids, ensure internal driveline components are optimally lubricated and protected from gas-sucking friction. Fresh fluids will also reach their operating viscosity quicker, helping incrementally reduce fuel usage.
Cooling system: Ensuring your fluid, hoses, radiator, water pump and thermostat are tip-top won’t increase gas mileage, but a properly functioning cooling system allows the engine and transmission to reach their operating temperatures, and achieve optimal mileage, quicker. A mechanic can inspect the cooling system in 30 minutes or so.
Ignition system: Engine efficiency depends largely on a tiny, precise spark from the spark plug to ignite a carefully mixed blend of air and gasoline. This process has been painstakingly engineered to achieve the best possible mileage, but when spark plugs are neglected, efficiency and mileage suffer drastically. A fresh set of spark plugs ensure the engine gets the best mileage possible, improves performance and adds reliability in cold-start situations.
“Newer vehicles tend to have spark plugs that require no attention for 100,000 kilometres or more,” says Kennaley. “But it’s important not to assume that’s always the case, and to check your owner’s manual, or ask your mechanic. … Spark plugs are easy to forget, but very important.”
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Simple checks to reduce fuel consumption and save money
