What’s Likely To Increase Fuel Consumption? (15 Causes & Fixes)

Any driver faced the problem of increasing fuel consumption. There can be many reasons for this phenomenon, and not always an increase in the gluttony of a car associated with a breakdown. The article discusses the causes of high fuel consumption and methods of dealing with this problem.

what's most likely to increase fuel consumption

What determines the fuel consumption of a car?

Cars consume different amounts of fuel depending on many parameters. Estimated consumption rates are indicated in the vehicle documentation, and you can check this fact with the dealer. For a technically sound vehicle, the most important factors are:

  • Road relief. When driving at constant acceleration, part of the engine power is spent on overcoming the friction of the wheels on the road. If the road is bad, then additional diesel fuel will be needed to maintain a high speed.
  • Vehicle weight. The greater the weight of the car, the higher the fuel consumption will be, since the motor will need additional power to move all the weight.
  • Vehicle speed. The higher the driver picks up speed, the more fuel will be needed for the internal combustion engine to move the vehicle.

Fuel consumption is indirectly affected by the type of internal combustion engine (air, turbocharged). Turbocharged cars are more fuel efficient because they provide additional speed by using the energy of the exhaust gases, and not by burning fuel (as is the case with an air engine).

15 Factors most likely to increase fuel consumption and their fixes

There are dozens of reasons that are most likely to increase fuel consumption. Some of the reasons are related to natural factors and do not indicate the presence of a breakdown – for example, the use of low-quality fuel and a harsh driving style. While other reasons may indeed be related to a breakdown – for example, engine failure or a clogged catalyst.

15 Factors most likely to increase fuel consumption and their fixes

Poor quality fuel

Low-quality fuel burns worse and gives less energy, so additional diesel fuel will be injected into the engine to maintain a high speed. Diagnosing the problem is quite simple – if the costs increased after visiting a new gas station, then the problem is in the fuel. The solution to the problem will be trivial – use up or drain the old “fuel”, and then refuel at a reliable gas station.

Using the heating or climate system

The operation of these devices is associated with the operation of the compressor, which receives energy from the rotating crankshaft. Therefore, the use of heating and climate systems requires additional fuel costs. Unfortunately, this situation cannot be corrected – either you use these systems, but then you will have to endure additional fuel consumption, or you do not use these systems, but the ride comfort will decrease.

open windows

Open windows allow oncoming air into the passenger compartment, which worsens the aerodynamics of the car and reduces speed. To increase speed, the engine burns additional “fuel”. The problem mainly manifests itself in the case of driving at high speeds, which can be used for diagnostics (when driving at low speeds, speed losses will be insignificant). The solution to the problem is trivial – keep the windows closed while driving.

Harsh braking and acceleration

If you use an aggressive driving style (brake sharply, make quick turns, change gears frequently), then you cannot avoid the increased cost of diesel fuel. To harmonize fuel consumption, you need to reconsider the style of driving.

flat tires

In the case of using flat tires, part of the “diesel fuel” is spent on overcoming the resistance of the roadway, which will negatively affect the speed of movement and lead to an increase in fuel consumption. You can fix the problem visually by flat tires, as well as using a pressure gauge. The solution is also trivial – just pump up the tires yourself or at a service center.

Clogged air filter

For the engine to work, it needs not only “fuel”, but also atmospheric air. However, normal air contains small particles of dust that can clog the engine, so modern cars are equipped with an air filter. If the filter in the engine is clogged, the air supply is reduced and the amount of fuel injected increases. You can establish a breakdown by such signs – pops in the exhaust system, unstable speed, and difficult start of the internal combustion engine.

The breakdown is solved as follows:

  • Open the hood and find the air filter, unscrew the fixing bolts, or remove the latches.
  • Remove the old air filter, if necessary, remove additional clamps.
  • Install a new filter, install the clamps, and tighten the fixing bolts/latches.

Cleaning dirty air filters is useless, so you need to buy a new filter to fix the defect.

Dirty fuel filter

The fuel filter is a spare part that is responsible for cleaning gasoline/diesel tanks from rust, dirt, and water. When it is clogged, the pressure in the system drops, and the electronic unit gives a command for an additional injection of diesel fuel. You can establish pollution by such signs – sharp shocks on the rise of the car, spontaneous braking, the car stalls at idle, the internal combustion engine trips.

To eliminate the breakdown, it is recommended to install a new filter, and the replacement method will differ depending on the design of the vehicle. Approximate algorithm of actions:

  • Open the hood and find the old filter. It looks like a small cylinder to which two or three hoses are attached.
  • Pull out the safety pin and clamps, unscrew the hoses, remove the old filter – fill the new filter with fuel and put it in place of the old one, and attach the hoses and clamps.

Failure of spark plugs

Due to the breakdown of the spark plugs, the ignition of the fuel in the internal combustion chamber is disrupted. To correct this problem, the ECU can increase fuel injection. It is possible to establish the presence of faulty candles by the following signs – a decrease in engine power, a long start and uneven operation of the engine, and a sharp stop of the internal combustion engine at high speeds. Spark plugs are changed like this:

  • Turn off the power to the car, open the hood, and find a rectangular block with spark plugs, open it.
  • Disconnect the bus that leads to power, carefully pull out the rail with the bus, and then unscrew the fixing bolts
  • Pull out the rail with the ignition coils, and then unscrew the spark plugs. Inspect them – if the end of the candle has turned red or brown, replace the part.

Throttle sensor failure (TPS)

Due to a malfunctioning throttle position sensor (TPS), the onboard computer will receive incorrect information that the engine is receiving excess air. To correct this situation, he will increase the petrol/diesel injection. It is possible to establish the failure of the TPS by the following signs – twitches and delays during acceleration, a sudden stop of the engine, and strong vibrations while driving. Solution:

  • The sensor is located on the front corner wall of the motor. Open the hood, find the TPS, and disconnect the power supply block.
  • Unscrew the two fixing bolts and remove the sensor. In its place, put a new device, tighten the bolts, and connect the power block.

Breakage of the lambda probe

The amount of oxygen in the system is controlled by a lambda probe, which is quite fragile. If it breaks down, the electronic unit may give the order to inject additional fuel into the engine, which will lead to excessive consumption of fuel. Symptoms of a breakdown of the lambda probe are floating idle, jerks during acceleration, and unstable engine operation.

Replacing the lambda probe is done like this:

  • On the exhaust manifold, remove the protective screen, warm up the engine to operating temperature, and then remove the negative terminal from the battery.
  • Find the lambda probe (it looks like a small cylinder with a wire), disconnect the sensor’s electrical connector, and unscrew the probe from the socket using a special screwdriver bit.
  • Take a new sensor and screw it into the hole, connect the electrical connector, install a protective screen, and restore power.

Clogged catalyst

A catalyst is a device that is located on the exhaust system and serves to neutralize gases. In the case of a very contaminated catalyst, the exhaust gases cannot quickly leave the car’s exhaust system, so the engine has to spend additional energy squeezing out the gases. The main symptoms of a clogged catalyst are poor acceleration, the engine stalls quickly, and resistance when you press the gas pedal.

Changing the catalyst is quite difficult – it is much easier to flush it:

  • Unscrew the lambda probe according to the instructions from the previous paragraph.
  • From the bottom of the exhaust system, unscrew the clamp nut, and then pull out the corrugation.
  • Buy a diesel particulate filter cleaner, close the exhaust with a plug, and pour the liquid through the hole for the lambda probe.
  • Substitute a bucket under the exhaust, after 10-20 minutes open the plug and release the liquid, rinse the system with clean water, and install the corrugation and the lambda probe in place.

If the flush fails, then there is a good chance that the catalyst filter cells have melted or are damaged. It will be difficult to dismantle the catalyst yourself, therefore, to solve this problem, it is better to contact a service center.

Damage to the airflow sensor (DMRV)

The mass air flow sensor (DMRV) performs similar functions as the lambda probe. It evaluates the amount of air that enters the engine, and if it breaks down, the control unit can send a command to increase diesel fuel. The main symptoms of a sensor failure are unstable idling speed, the car starting to jerk, and the engine starting very poorly. Change the sensor like this:

  • Open the hood, find the DMRV (it looks like a large block to which the pipe is connected), and then pull out the electrical connector.
  • Depress the clamp of the rubber corrugated pipe, and then remove the pipe itself. Unscrew the fixing screws with a screwdriver.
  • Pull out the sensor and inspect it – you will see numbers on the side. Buy a new DMRV with similar numbers, and then install the device in reverse order.

Clutch disc wear

If the clutch disc breaks, there is also an increased consumption of gasoline/diesel, which is associated with the peculiarity of gear shifting in the car. Symptoms of disc failure – problems with gear shifting, the appearance of sharp sounds when switching, slipping, and jamming of the brake pedal. Unfortunately, it is problematic to replace the clutch disc yourself, so it is recommended to contact a car service to replace the disc.

Deterioration of the piston group of the internal combustion engine

Scratches and microcracks can appear on engine pistons, which will lead to energy leakage and increased fuel consumption. This problem is especially critical for older cars with a mileage of more than 100 thousand kilometers. Symptoms of a breakdown are blue smoke from the exhaust pipes, increased oil consumption, and jolts while driving. It will also be problematic to carry out repairs yourself, so it is better to contact a car service with a malfunction.

High engine wear

Excessive fuel consumption can appear not only when the piston group is worn, but also when the engine is worn as a whole. The malfunction is typical for old cars with high mileage at the level of 120-150 thousand kilometers. The main signs are a very tight start, engine tripping, increased oil consumption, and strong smoke from the exhaust. A worn-out engine must be replaced, and it is recommended to entrust all the necessary work to a master in a car service.

Owners of older vehicles face increased fuel consumption. In older cars, the engine, piston system, transmission, and many sensors are often worn out. Repairing such cars is a difficult and often expensive task. If you recently bought a car, and after a short time, fuel consumption has increased dramatically, then you should not panic. The problem may be in natural factors for example, due to the use of the climate system, flat tires or refueling with low-quality gasoline.

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