How to Drive a Turbo Diesel Car with Manual Transmission Efficiently

Choose the right gas station to trial and stick with it for duration of the steps below. Not all diesel fuels are equal quality. Some are "dirtier" than others, and will negatively affect your mileage. Switching stations usually means switching the specific type of diesel fuel, so stay consistent. Find a gas station that offers a low price on diesel fuel, and also offers self service diesel pumps. Some stations offer further discounts if you pay with cash or debit. Your car dealership should be able to recommend a gas station that is best for your car.

Ensure that your vehicle's engine has been serviced and that all glow-plugs are operating efficiently. Inefficient functioning of your glow-plugs means inefficient engine starts, which wastes fuel.

Inquire at your car dealership about fuel additive for your diesel engine. Many will increase your mileage while helping keep your engine clean. Factor the cost of this additive, and how often you are expected to add it, onto the cost of your fuel.^[1]

When you go to the pumps, try your best to always fill your car all the way up. It will make measuring your trial much easier.

Reset your vehicle's "Trip" odometer whenever you fill up.

Pay attention to your gas-cap warnings. For example, many diesel vehicles have a "DO NOT TOP OFF" warning written on them. If present, heed this warning and communicate it to gas station attendants filling your vehicle.

When starting your vehicle, always make sure your glow plug indicator is indicating that it is ready for ignition. This usually means that your glow-plug light is no longer illuminated. Turning the ignition before your glow plug is ready may waste fuel. During some colder weather, some car dealerships recommend that you "double glow" to get the glow plug hotter. This consists of glowing your plug, and when it indicates "ready", turning off your ignition, and repeating the glow again before turning your ignition. This may allow for a more efficient start in some vehicles at certain low temperatures. Besides, glowing your plugs consumes no fuel, so there is no disadvantage.^[2]

Driving style makes all the difference with fuel economy, whether it is in diesel or gas cars. This is the single biggest change you can make to see dramatic improvements in your fuel economy. If optimal fuel economy is your goal, be ready to sacrifice any aggressive or "performance" driving habits you may have.^[3]

Each engine has a "sweet spot" where it is operating at its most efficient. These are normally "highway speeds" somewhere around 60 mph (100 kph) in 5th gear but it will vary from car to car. Accelerating to that habitual "20% over the speed limit" will negatively impact your fuel consumption considerably.

If you have cruise control in your vehicle, use it regularly so that you don't subconsciously "creep" your speed upwards. Your on board computer is better at efficiently maintaining speed than you are. Humans tend to "over correct" by accelerating a little too much, braking or decelerating, applying the gas pedal again, etc. This wastes fuel, a little at a time.^[4]

When driving, gear up as soon as you can. Get into the habit of spending the least amount of time possible in the lower gears. Conversely, gear down (or speed up) whenever you hear your car struggling in a high gear. You should not feel a strain on your transmission, but most people tend to wrongly delay their shifting to higher gears by several hundred RPM. You will feel a slight decline in your acceleration when you shift sooner, but once again, try hard to shed any addiction to power, speed, and acceleration. Those things are incompatible with optimizing fuel mileage. Try hard to retrain yourself to the new shift-times.^[5]

Your fuel mileage will realize large efficiencies the more you drive uninterrupted. A "road trip" on the highway is the ideal case since you can maintain a relatively steady speed, not be idling at stop signs/lights very often, and not be restarting your vehicle too often. With any other type of trip (to work, to a friends, etc.) stay on highways for as long as you can.

Engine braking (gear down) to slow or stop, in modern diesel engines uses less fuel than just braking, or coasting to a stop either in neutral or by holding the clutch down. This is because modern diesels have direct injection which is computer controlled. At idle, the injectors are delivering a very small amount if fuel. When you use the engine to slow the vehicle at speed (throttle closed), the injectors shut off. While the engine braking (gearing down) method of stopping is easier on your brakes, it is harder on the clutch. Brakes cost less than clutches do, so it depends on the situation for what the better choice is.

Many drivers forget that every electrical convenience being operated consumes fuel. Try to keep defrost, seat warmers, radio, fans, etc at a minimum. Turn off your full lights during the daytime and let your daytime running lights do the rest. Also, many defrost options will not turn off automatically, so monitor them diligently. Air conditioning is the worst fuel-consumer. Use it sparingly if you wish to conserve fuel. Turning the windows down also wastes fuel, although some people argue whether or not it wastes more or less than air conditioning, and this fact varies at different speeds. The fact is, any time air is being removed from the passenger cabin through an opening, it is creating some degree of drag from an aerodynamic standpoint, however small. Simply be aware of it. Also, while your engine is turned off, limit electrical convenience use (radio etc) since the car will have to recharge the battery accordingly after it starts.

Some dealerships offer "chips" for your onboard computer that upgrade your vehicles fuel economy. Many people purchase these expensive chips without factoring in their cost. These chips should be viewed as an investment. Armed with numbers of your regular fuel consumption, average speeds, etc, you should calculate how long it will take the chip to pay for itself. Some discover that it is longer than they plan to own the vehicle, making it a foolish purchase for them. Make the right financial choice for yourself, since saving money on fuel consumption is what it's all about.