By Jim Kerr

You may have noticed your fuel economy has recently dropped. Winter has come early to much of Canada and the snowy roads and icy intersections use more energy to get a vehicle going. Cold temperatures mean longer engine warm up times and thick oils in drivetrains. It isn’t unusual to see fuel economy drop by half during extremely cold temperatures.

There are many ways to improve fuel economy, especially in cold weather. Keeping tires inflated properly will help. Parking in a garage, even if it is not heated, tends to keep the vehicle warmer so it takes less fuel to bring it up to normal operating temperature and new spark plugs can help save fuel if they have many miles on them. Perhaps the biggest improvement can be made by ensuring the engine’s thermostat is operating properly. A thermostat that opens too soon reduces interior heat but it also takes longer for the engine to achieve operating temperature. A longer warm up period uses much more fuel.

For every traditional way of improving fuel economy, there are a thousand “fuel saving devices” on the market. You find them advertised in magazines, offered for sale at fairs and trade shows and promoted on the Internet. The sales pitch sounds good. The devices look high tech and there are reams of supporting statements that the devices work -but do they really?

While I have tested a few of these fuel saving devices and found no real improvement in fuel economy, it would be nearly impossible to test all the units offered in the marketplace. Even the U.S. Government Environmental Protection Agency (EPA) hasn’t tested all of them, but
they have tested many.

The EPA evaluated fuel saving devices and additives in several categories. Some devices bleed air into the intake manifold to lean out the fuel mixture. Some of these devices pass the air through a liquid first. Of all the systems tested, only one showed a slight increase in fuel economy but that one also caused higher emissions out the tailpipe. Liquid injection systems were also tested, with the same result as the air bleed type devices – no improvement in fuel economy.

Ignition system enhancers are another type of fuel saving devices. While there may be advantages to high performance ignition systems if you are going racing, original factory ignition systems are more than capable of firing the spark plugs under all normal driving conditions. All that is needed is an occasional tune-up, including new sparkplugs and plug wires. None of the ignition system enhancer devices improved fuel economy.

Some devices connect to the fuel lines. Fuel line heaters/coolers and magnets (designed to ionize or change the molecular structure of the fuel) fall into this category. I often tell my classes that placing magnets on the fuel line does work, but only if they are strong enough and you are following close behind a big truck. Then the magnetic attraction might pull you along. Some of them even believe me for a second!

Mixture enhancers are devices mounted in the intake air stream to help the mixing or vapourization of the fuel. I have looked at several of these and found the directions for installing them suggest also installing a new air filter, sparkplugs and checking the ignition timing if possible. In other words, perform a tune-up while you install the device and fuel economy will improve. Guess what causes the improvement. Hint: it isn’t the mixture enhancer.

Fuel and oil additives didn’t fare any better. None tested by the EPA improved economy.

Interestingly, there were some devices that did improve economy slightly without any increase in emissions. What were they? Driving habit modifiers. These devices use lights or sounds to tell the driver to accelerate slower or shift gears. Are they worth it? Probably not. Driving style has a huge impact on fuel economy but you can change your driving style without a device telling you to accelerate slowly or reduce speeds.

My advice: stick to basics. Keep your vehicle maintained, tires inflated and drive for economy. Save the money you might spend on fuel saving devices and spend it on maintenance instead. The U.S. Federal Trade Commission (FTC) sums it all up. The FTC warns you to be wary of any gas-saving claims for automotive devices or oil and gas additives. “Even for the few gas-saving products that have been found to work, the savings have been small.”

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