Use system maintenance to reduce fuel consumption

Posted 21 May 2006
© by Norris Schleeter and Melanie McCalmont

We are happy to authorize reprints of this article. Please contact us.

Reducing your car's fuel consumption starts with knowing how your car is a SYSTEM of components--the engine, the car body, and the driver.

The components all affect each other and change fuel consumption, sometimes on a daily basis. Here's some NEW tips for increasing your miles-per-gallon:

Engine component

• ADD-ON: Beware of any add-on items that claim fuel savings. Items like special air filters or intake tornados are just scams. If they really worked, the car maker would buy them and install them on every new car! Instead, buy a new, "original equipment" quality air filter and your engine will breathe easier and burn less fuel.

• ENGINE INDICATORS: The "Check Engine" warning light coming on or staying on means that the tailpipe emissions are unbalanced or off specification. The car might seem to run fine—but if the emissions are affected then so is the fuel consumption. Get the car checked out as soon as possible and ask about warranties on the emissions system. See our section on secret warranties.  If your car is a 1995 or older model, keep in mind that the on-board computer is not as interested in monitoring emissions and may not turn on the "check engine" light if an emissions problems is present. [Other warning lights with similar impact are "Service Engine Soon," "Exhaust Temperature," or the pictograph icon of an engine. Check the owner's manual for the correct malfunction indicator light (MIL) for your car.]

• OXYGEN SENSOR: Replace the Oxygen Sensor on your pre-1995 car. A new oxygen sensor (OS) could quickly pay for itself in fuel savings, if it's worn out. Especially suspect are "single wire" sensors (photo at right) because they have short service lives and degrade after 75,000 miles. (Multi-wire sensors usually last twice as long.) The OS is NOT usually mentioned in the owner's manual but can make a huge difference in gas mileage. Look for your oxygen sensor type, installed on the exhaust manifold or exhaust pipe near the engine. Also, if your car is a 1995 or older model, keep in mind that the on-board computer is not as interested in monitoring emissions and may not turn on the "check engine" light if an oxygen mixture problem is present.

• MOTOR OIL: Switch to synthetic motor oil. Your engine will run smoother and cooler and thus get better gas mileage. Synthetics can also delay oil changes to a longer interval which will pay for itself, so the small additional cost of synthetic is really free. Learn more about motor oils...

• POWER: Buy a car with less horsepower. More power = more fuel burned.

Car body component

• ALIGNMENT: Wheel alignment can also have an adverse effect on fuel mileage. If the tires are not in a perfectly straight line the extra drag will cause heat to buildup in the tires and a slightly increased drag on the engine (see photos below). Check the tires for unusual edge wear by running your hand across the tread of the tire and feel for low spots, high spots or just less tread depth than another part of the tire. Adverse tire wear indicates an alignment is needed. If the tires look good, let 'em roll.

• SNOW TIRES: Don't buy snow tires unless absolutely necessary. Snow tires cause mileage to go down because they have taller, wider-spaced tread blocks to increase traction which causes increased rolling resistance on dry pavement--and burns more fuel. Driving on snow tires in the summer is a huge waste of rubber and gasoline.
  
• PSI: Keep tires properly inflated. Mushy tires adhere to the pavement and make your engine work harder to drag your car around. Tire pressure that's a few PSI more than what is recommended can save gas and increase tire life. Just don't overinflate!
  
• WEIGHT: Heavy cars use more fuel. Clean out the cargo area of stuff you're not using, especially those sand bag tubes for winter traction. That extra 150 pounds in the car takes fuel to move it down the road!
  
• HUBS: On 4x4 trucks and SUVs, check the manual locking front hubs and confirm they are in the "unlocked" position. Why? If hubs remain locked then additional drive train parts are engaged unnecessarily which burns fuel to operate. Some SUVs and trucks have part-time four-wheel drive just to reduce fuel consumption on dry roads. Automatic front hubs can be inspected by your technician to confirm proper operation.
  

• TAILGATE? Lose it. Pickup trucks with an open bed will benefit from an alternative tailgate that allows air to flow more efficiently across the vehicle. There are many types available including nylon nets and metal grills, or the tailgate could simply be removed and stored until it is needed for hauling.
  
• RACKS: Remove the bike/ski rack from the roof of your car when not in use--less air drag means less fuel burned (and the rack feet won't be digging into the paint unnecessarily.)

Driver component

• FUEL TYPE: Experiment with different brands and types of fuel. Low grade gas has less BTU energy by design. Higher BTU energy premium gas may save you money by allowing you to use less throttle. Use my Gas Mileage Worksheet to track and compare results. Your car may prefer one gas type over the other. I have heard reports from several customers that switching down to regular "cheap" gas actually caused the gas mileage to decrease resulting in no real savings at all. Best of all, learn about and consider an alternative fuel vehicle (AFV).

• COLD OPERATION: Don't drive on extra cold days. Cold weather is when cars use the most fuel. When the engine is very cold, it takes more gas to get it started and up to temperature. In bad-weather traffic, once again time spent in stop and go conditions is worse--causing more gas guzzling. Cold weather accessories, such as heaters, defrosters, wipers, and seat heaters, cause extra alternator loads--which creates engine drag and lowers gas mileage.

• TIME: Arrange flexible work hours to skip traffic jams and ultimately spend less time in the car. When you're stuck in a traffic jam and not moving--your miles-per-gallon is ZERO.

• PLAN TRIPS: Several short trips can use twice as much fuel as a longer warm-engine trips covering the same distance. Plan your errands and routes to reduce short trip engine shut down and re-starts.
  
  
• ACCELERATION: Use less throttle, accelerate smoothly, look farther ahead at the traffic and anticipate slow downs by backing off the gas evenly and early. More gas is burned on acceleration. So what if someone goes by? You'll be saving gas and brake wear by not being the first one to the red light.
  

Posted 21 May 2006
© by Norris Schleeter and Melanie McCalmont

We are happy to authorize reprints of this article. Please contact us.