What can cause a sharp increase in fuel consumption of the car, and how to avoid it

Against the background of constantly deteriorating economic situation the question of fuel economy becomes particularly acute for the drivers. And if the fuel consumption suddenly increases, it only aggravates the problem, because in addition to the frequency of trips to the gas station, the motorist feels a serious blow to the wallet. What causes such troubles, and how to avoid them?

Technical fluids

The most obvious reason for a sharp increase in automobile fuel consumption is refueling with low-quality fuel. If you use DT or gasoline of unsuitable quality and chemical composition, the composition will burn much faster or incorrectly, because the electronic components in the vehicle will start enriching the mixture, giving more fuel in the combustion chamber.

To exclude such phenomena, it is enough to be responsible in choosing a gas station, pouring into the tank only proven fuel at reputable gas stations.

Also growing gasoline or diesel consumption can be explained by the use of unsuitable or low-grade engine oil or failure to comply with the terms of its replacement. The problem is solved by cleaning the system of low-quality lubricant and pouring in a new composition.

Problems on the electronic control unit side

Any internal combustion engine in a modern car is controlled by advanced electronics and interacts closely with a multitude of systems and controls. The ECU adapts the operation of the actuators (fuel pressure, throttle opening level, injector intensity and much more) to the operating conditions of the vehicle, taking into account the data received from various sensors.

If any of the sensors begins to send incorrect information, the ECU picks up the wrong settings, which causes the fuel mixture to burn incorrectly, resulting in higher fuel consumption.

Fortunately, in such cases, the “Check Engine” icon is displayed on the dashboard, indicating that an urgent equipment check is necessary. Having detected such a signal notice, you should immediately go for help to a car repair shop, where a professional readout of errors will be performed, followed by their elimination or replacement of the failed sensor.

Fuel filter

Often the problem with increased fuel consumption is due to a clogged fuel filter. Under such circumstances, fuel pressure drops sharply, and the ECU sends a command to hold the injectors open for a longer time to adapt the pressure readings.

Theoretically there is no problem with this, but when the filter is clogged the pressure often jumps and is unstable, so the electronics trivially does not have time to adjust the correct operating parameters, causing unbalanced fuel supply to the combustion chamber with unpredictable, usually high fuel consumption.

Air filter

Another consumable that has a direct impact on fuel consumption is the air filter. It’s no secret that fuel consumption is directly related to air intake, and if this process gets complicated, it becomes difficult for the engine to draw air in because the filter is clogged with dust and dirt. And if it becomes heavily loaded, fuel consumption skyrockets. That’s why the air filter needs to be replaced every time the lubricant is renewed.

Mass air flow sensor

This element monitors air consumption by estimating the volume of incoming masses in the combustion chamber. If the ducts through which the air flows into the system are leaky, the measurement results become inaccurate. The result is an incorrect stoichiometric ratio of the combustion mixture, and the internal combustion engine malfunctions with all the troubles.

Therefore, when checking the vehicle, it is necessary to first evaluate the mass fuel flow sensor DMRV.

Elements of the piston group

During the operation of any vehicle, the elements of the piston group are subject to inevitable wear and tear. If the mileage exceeds 100 thousand kilometers, such phenomena are evident. In engines with such mileage the increased fuel consumption is often explained with problems with compression in cylinders. If it is low, the engine efficiency level will decrease, and to achieve the required efficiency it will start burning a lot of fuel.

Naturally, part of the fuel-air mixture will remain unburned, since the initial operating parameters are adapted to standard compression. Because of this, cars with “age” often consume more gasoline/DT than expected.

Failed spark plugs

With improper gap selection, dirty or naturally worn spark plugs, a spike in fuel consumption is a natural consequence. If you are not willing to overpay for fuel at a network gas station, it is better to change the spark plugs every 30 thousand kilometers or as they wear out.

Problems with lambda probe

This sensor is responsible for accounting the amount of oxygen in the exhaust gases and maintaining the correct proportions of the fuel-air mixture. If the ratio of oxygen to gasoline is disturbed, the car becomes more “voracious”. Usually damage to the oxygen sensor is due to fouling on the ceramic rod. It can be removed with your own hands, using orthophosphoric acid or heating the surface and then cooling.

Driving style

Switching to a more aggressive driving style with quick starts and braking is a weighty explanation for a sharp rise in fuel consumption. Such driving style greatly increases fuel consumption regardless of engine capacity, fuel system type and related units.

To reduce consumption it is enough to reconsider the driving style, eliminating jerking. You should also start to practice coasting and not abuse the brake pedal without an urgent need. In this case you can reduce fuel consumption and increase the service life of the power unit.

Road Conditions

Frequent driving on mountain slopes affects fuel consumption. In this case, when driving downhill, the car “eats” less fuel than when driving uphill. This is where physics comes into play. Also the atmospheric pressure has a special influence on the indicators of the flow meter. The higher the car is above sea level, the more fuel is consumed.

Planning a trip to hilly or mountainous terrain, you need to fill up the tank, as well as stick to a smooth driving style, avoiding sudden maneuvers, jerks and brakes.

Weather conditions

Unfavorable weather conditions are also mentioned among the reasons for a sharp increase in fuel consumption. Violent wind, low or excessively high temperatures, heavy rainfall, snowfall and other vagaries of weather seriously affect the amount of fuel burned in the vehicle. If a storm is coming, it is better to sit it out and hit the road later. In addition, under such circumstances there is a risk of accidents, so if possible the trip should be postponed.

Auxiliary Devices and Equipment

Sometimes a car starts to burn more fuel not due to technical problems, but due to the work of standard equipment and additional equipment.

Climate control, powerful car acoustics, light devices and other serious electric energy consumers contribute to increase of loads on the generator, which is in close contact with the engine via belt drive. And the greater power consumption for generator rotation leads to an increase in the engine’s “appetite”.


Oddly enough, but tires also strongly influence fuel consumption. For example, low tire pressure results in higher rolling resistance, as the system is forced to expend some fuel to overcome resistance. In order to improve fuel consumption and range, many hybrid electric cars and cars are equipped with hard tires with a narrow profile.

The question may also arise as to whether rim radius and tire parameters affect fuel consumption. In this case, not the size, but the weight of the wheels is taken into account. But everything is interconnected here: the more dimensions of wheels, the more their weight and, actually, the weight of the whole car. At operation of the car in the city line it considerably raises fuel consumption.

Is it possible to reduce fuel consumption without visiting auto service center?

It is possible to essentially reduce fuel consumption without a trip to the service station only if there are no serious technical problems in the car. Therefore, you should first of all estimate a condition of an air filter and level of pressure in tires.

When driving a car, you should adhere to an optimum speed mode, avoiding abrupt starts and brakes. You should also avoid excessive tuning and heavy overloading of the car.

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