The situation when the gas station emptys the wallet faster than usual, is familiar to many car owners. It seems that the routes are the same, traffic jams have not increased, and the arrow of the fuel level indicator treacherously creeps down after every hundred kilometers. Spending spikes It is always a signal that cannot be ignored, as it may indicate hidden faults or the need for urgent adjustment of engine systems.
It is important for the driver to understand that perfectThe sensing system declared by the manufacturer in the passport is almost impossible to achieve in real urban conditions. Factory figures are often obtained in ideal laboratory conditions or when driving at a constant speed on the track. However, if the difference between your real cost and passport exceeds 15-20%, you should look for the data. specific technical or operational reason overspending.
In this article, we will discuss in detail the main factors that affect the appetite of your iron horse. We will consider both mechanical problems and features of the vehicle management, so that you can independently conduct the initial diagnosis and understand where to go next - in the service or at the nearest refueling station for cheaper fuel.
Effect of the technical condition of the engine and ignition system
The most common reason for increased fuel consumption is the incorrect operation of the ignition system. If the spark is weak or is supplied at the wrong time, the fuel-air mixture does not burn completely. As a result, some of the gasoline simply flies into the exhaust pipe, without doing the useful work of pushing the pistons.
Particular attention should be paid to spark plugs. Coar on electrodes, increased gap or simply developed resource lead to ignition misses. The engine begins to work unstable, triple, and electronics, trying to level the speed, forced enrichmentWhich leads to a direct overspending.
Also critical is the condition of high-voltage wires and coils. Breakdown of wire insulation in wet weather can lead to the fact that the current goes “by the mass”, not reaching the candle. In modern systems with individual coils, the malfunction of one of them is immediately recorded by the control unit, but in older models the problem can remain hidden for a long time.
Replace spark plugs strictly according to the manufacturer's regulations, even if visually they seem normal. The electrode materials degrade imperceptibly to the eye.
And we should not forget about compression. If the valves burn out or the piston rings lie in, the pressure in the cylinder drops. The engine loses power, and to maintain the usual pace of movement, the driver has to push deeper on the accelerator pedal, burning more fuel.
Problems with air supply system and fuel system
For perfect combustion, a precise balance between the amount of air and gasoline is required. This is the responsibility of the mass air flow sensor (MARD). If it is contaminated or malfunctioning, it can transmit incorrect data to an electronic control unit (ECU). The computer thinks that more air is coming in than it really is, and it is pouring excess fuel.
A clogged air filter is another classic enemy of efficiency. The engine becomes difficult to “breathe”, creates a thinning, and the mixture becomes overenriched. Check the condition of the filter can be visually: if there is no light through it, and it itself is gray or black, it must be changed.
In the fuel system, problems can be associated with nozzles. Over time, they can coke or, conversely, begin to “pour” due to wear of the needle of the sprayer. Instead of a small fog that burns instantly, large drops of gasoline fall into the cylinder, which do not have time to burn completely.
- 🔧 DMRV - a sensitive element that is afraid of dust and oil; it must be cleaned with special means, without touching the threads.
- 🔧 RXX - the idling regulator also affects the stability of the engine and the consumption at stops.
- 🔧 Fuel filter If it is clogged, the pump works with overload, and the pressure in the ramp drops, breaking the spray torch.
How often do I change the fuel filter?
On modern cars with a submersible pump, the filter is often changed in assembly with a pump module every 100-120 thousand. km. On older models with a remote filter - every 30-40 thousand. km. Dirty filter can cause power drop and jerks during acceleration.
Sensors, Electronics and Software
The modern car is a computer on wheels. If the machine’s brains receive incorrect information, they make decisions. The lambda probe (oxygen sensor) is on guard of ecology and economy. It analyzes the composition of the exhaust gases and adjusts the fuel supply in real time. A “tired” lambda probe can understate the readings, making the ECU think the mixture is too poor, and increase the supply of gasoline.
The coolant temperature sensor (CTP) also plays a key role. When starting a cold engine, the ECU always operates in warm-up mode, supplying more fuel. If the sensor is faulty and shows that the engine is cold when it has long been warmed up, the “warm-up” mode may never turn off, which significantly increases the appetite of the machine.
Software (firmware) is also important. Chip tuning, made by illiterate specialists, often removes environmental restrictions in favor of power, which automatically leads to an increase in consumption. Sometimes it helps to update the firmware to the latest factory version, if the manufacturer has released a patch that optimizes the engine.
It is important to conduct computer diagnostics for any suspected electronic failures. Errors may not burn on the dashboard as Check EngineBut remain in memory as "Pending" (waiting), affecting the operation of the systems.
Chassis, transmission and rolling resistance
It’s not just the engine that affects how much gasoline you burn. If the car is hard to move, it will consume more energy. The first enemy here is the pressure in the tires. Flowed wheels increase the spot of contact with the road, which dramatically increases rolling resistance. The difference in flow rate between wheels with a pressure of 2.0 bar and 2.4 bar can reach 5-7%.
The scaling brake calipers are a frequent and dangerous problem. If the calipers guides are acidified, the pads can constantly slightly press the disc even when you do not press the brake pedal. The car is constantly "braking itself", the engine overcomes resistance, and the fuel is pouring. You can check this by driving and carefully touching the wheels (caution, you can get burned!).
The wheels are another important parameter. If the angles of the wheels are broken, the tires wear out unevenly, and the car holds the trajectory worse, requiring constant steering adjustment. This creates additional resistance.
| Problem. | Impact on expenditure | How to check |
|---|---|---|
| Low tire pressure | +3...7% | Cold gauge |
| Sour calipers | +10...15% | Heating discs after driving |
| Wrong fall-and-fall | +2...5% | Stand at the car service station |
| Old transmission oil | +1...3% | Visually (color, smell) |
In the transmission, it is also worth monitoring the state of the oil. In mechanical boxes, the old, thick oil creates more resistance when the gears are rotated. In automatic transmission machines (ACPs), late fluid replacement leads to incorrect operation of the hydraulic transformer and untimely switching, which also hits the pocket.
Regularly checking tire pressure is the easiest and cheapest way to reduce fuel consumption without visiting the service.
Driving style and operating conditions
Often the reason is not in the car, but in the right leg of the driver. Aggressive driving with sharp accelerations and braking is a guaranteed way to increase consumption by 20-30%. The engine in the maximum speed mode consumes a huge amount of mixture, and the energy spent on acceleration is then uselessly extinguished by the brakes.
Prolonged warm-up of the car on the spot is a habit that came from the past. Modern motors are more effective in warming up in motion at moderate load. Standing at idle speeds for 10-15 minutes burns a liter or more of fuel, while the mileage does not increase.
Using air conditioning also comes at a price. In the urban cycle included Climate control can increase consumption by 1-2 liters. However, at high speeds (the track) it is more profitable to turn on the air conditioner than to open the windows, since open windows create aerodynamic drag comparable to a parachute.
- 🚗 Predictability Look far ahead, drop the gas before traffic lights, using inertia.
- 🚗 Turnover Try to keep the engine in the range of maximum torque, without unwinding it to cut off.
- 🚗 Route. - detour traffic jams are sometimes longer in kilometer, but more economical in time and fuel.
⚠️ Attention: The coast down on a neutral gear on modern injection cars does not save fuel, but on the contrary, increases its consumption. When braking the engine (in gear), the fuel supply is completely blocked (0 l / h), and at idle speeds, the mixture continues to be supplied to maintain the engine.
Additional equipment and aerodynamics
Any change in the aerodynamics of the body affects the flow rate, especially at speeds above 80 km / h. The trunk on the roof, even empty, creates air swirls. If you are not using it right now, it is better to remove it. The same applies to luggage boxes ("baules") and bicycle fasteners.
Excess cargo in the trunk is a constant weight that the engine has to carry with it. Every 50 kg of additional cargo can increase consumption by 1-2%. It is worth considering whether you need to carry a full set of tools, canisters with oil and winter tires all year round, if this is not directly necessary.
The tuning also makes its own adjustments. Installation of wheels with a larger diameter with a wide rubber ("rollout") always worsens aerodynamics and increases weight, which negatively affects efficiency. Wide discs create more rolling resistance and accelerate worse.
☑️ Pre-travel checks
It is also worth mentioning the quality of the fuel. Low-octane gasoline burns faster and less efficiently. The ECU tries to compensate for the detonation by changing the angle of ignition advance, which often leads to loss of power and an increase in consumption. The gas station savings could come out sideways.
⚠️ Attention: The use of dehydrator additives (water removers) and octane correctors makes sense only when the quality of fuel is questioned. Continuous use of “magic bottles” instead of repairs will not solve the problem of high flow, and in some cases can disable the lambda probe and catalyst.
Diagnostics and methods of troubleshooting
If you have excluded all external factors, and the cost is still high, a professional diagnosis is necessary. Start with the scanner connection. It will show corrections of fuel supply, position of the throttle valve, readings of the lambda probe in real time and the angle of ignition advance.
The compression measurement will allow to assess the mechanical state of the engine. If the compression in one of the cylinders is much lower than in the rest, you will need to disassemble the engine to replace the rings or grind the valves. It is expensive, but it is necessary to restore the resource.
Checking the pressure in the fuel ramp will eliminate problems with the fuel pressure regulator (RDT). If the RDT "pours" the reversal or does not hold the pressure, the mixture will be disturbed. Also checked the performance of the fuel pump – a weak pump will not be able to provide the desired torch spray nozzles under load.
What is an endoscopy of an engine?
This is a diagnostic method without disassembling the engine. Through the opening of the spark plug, a camera is inserted into the cylinder, allowing you to see the condition of the pistons, valves and the presence of soak. It helps to identify problems at an early stage.
It is important to approach the problem in a comprehensive manner. Replacing one sensor may not give a result if the catalyst is clogged in parallel or the nozzles flow. Only a consistent check of all systems will allow you to find the true cause and return the car to its former economy.
Is it true that winter spending is always higher?
Yeah, that's true. In winter, the engine warms up longer, runs on an enriched mixture. Winter rubber has greater rolling resistance, and in the trunk lies heavy snowshoe. In addition, the included seat heating, glass and stove consume a lot of energy, causing the generator to load the engine.
Can bad engine oil increase your consumption?
Indirectly, yes. Old, lost properties oil creates more friction in the pairs of friction. Also, if the oil burns (gets into the combustion chamber), it clogs the catalyst and changes the readings of the lambda probe, which can lead to incorrect operation of the engine control system.
Does the replacement of the air filter affect the dynamics?
Yeah, if the old filter was heavily clogged. Replacing the new one will provide better airflow, which will improve cylinder occupancy. The engine will become easier to “breathe”, the response to the gas pedal will improve, and the flow rate may decrease slightly or remain the same, but with better dynamics.
Should I wash the engine if it is dirty?
In terms of consumption, no, the dirt on the engine block does not affect the combustion of fuel. However, heavy pollution can lead to overheating (the dirt works as a thermal insulator) and makes it difficult to find oil leaks or antifreeze during diagnosis. Washing is necessary for ease of maintenance, not to save gasoline.
How often should I do a computer diagnostic?
Preventive diagnosis is recommended once a year or every 15-20 thousand km of mileage. If the lamp is on fire, Check Engine or symptoms (failures, triplicities, high consumption), diagnosis is needed immediately, regardless of mileage.