A headache for motorists is high gas mileage. Prices at gas stations regularly increase, so more and more of the family budget has to be spent on fuel. Although sometimes it is enough to devote a couple of hours to your iron horse for diagnostics with easy repairs, and this time will return in the form of saved liters per hundred kilometers.
Of all the consequences that affect efficiency parameters, it is customary to distinguish two main reasons for high fuel consumption:
- direct (poor performance of individual components or elements, as well as their complete failure to operate);
- indirect (factors that are largely not directly related to design changes during operation).
To identify such faults, in some cases you can carry out visual diagnostics yourself, and then contact professionals.
Lambda probe
Failure of the oxygen sensor in most cases occurs due to the use of leaded fuel. Residues of lead oxides cover the working part of the assembly. In this regard, the injectors begin to add more gasoline to the fuel mixture. This chain leads to an increased level of CO in the exhaust gases. Often it is by this indicator that you can determine that the lambda probe needs to be replaced or repaired.
Lambda probe location
Computer engine diagnostics can also indicate a non-functioning sensor. In this case, you can simply replace it with a new one. However, this is quite an expensive action.
The approximate cost of a new original lambda probe for a Japanese foreign car will be about $400.
A cheaper option for such repairs is to replace the unit with a Bosch sensor, which is a spare part for VAZ cars.
Candles
Low-quality gasoline has a detrimental effect on the operation of spark plugs in the engine. Replacing them with new ones will help in the fight to reduce fuel consumption. But when purchasing a kit, you need to check for a correctly installed gap.
How to identify low-quality candles
After all, even in branded stores, suppliers can supply low-quality goods. Then the purchase will be useless. Some products can cost up to $40 each.
Filters
Regular car maintenance will help you overcome increased fuel consumption. During this procedure, it is advisable to ensure that all filters required for this period of operation are replaced:
- oil;
- fuel;
- air.
You shouldn’t expect much return from this action, but the positive effect will be noticeable.
Electrical part
Electrical leaks may occur due to contamination of the switch-distributor or high-voltage wires. This affects the quality of combustion of the fuel mixture in the cylinders. Incomplete combustion occurs. Therefore, you can check the electrical circuit for breakdowns. In case of obvious contamination, you can clean or partially replace damaged armor wires.
Catalysts
This element of the fuel system helps combat air pollution. But at the same time the car loses a little power.
Appearance of the catalyst
If the catalyst is faulty or is not in place at all, then this may also be the reason why the car consumes a lot of gasoline.
High idle speed
Incorrect adjustment of the idle speed level significantly contributes to consumption during warm-up, as well as when stopping the car with the engine not turned off.
For stable operation of the power unit, it is necessary to clearly set the speed specified on the passport.
Advance angle
More experienced drivers also point out to their novice colleagues that the ignition timing is adjusted correctly. A signal for this can be both unstable idling and problems with starting the car. If such symptoms appear regularly, then minor intervention in adjusting the distributor will be required.
Mass air flow sensor
An important element of a modern car is the fuel consumption sensor. Its functions include monitoring the air mass that is supplied to the engine.
What does a mass air flow sensor look like?
The correct ratio of fuel and oxygen results in maximum efficiency and power of the vehicle.
If the mixture is over-enriched, this affects greater fuel consumption.
Injectors
Dirty injectors do not spray fuel into the combustion chamber. More often it simply flows in for enrichment. To avoid this, you will need to flush this part of the injector. This work is performed at specialized stands in a car service center or at home.
The regularity of this procedure depends on the quality of the fuel used.
In Russian reality, the interval between maintenance should not be more than 10 thousand kilometers. If the budget allows for a replacement, then it would be more advisable to install new kits.
Compression
To check this parameter, you will need a special device - a compression meter. It is advisable to have it in the garage to check compression in the cylinders. The approximate cost of the device is 10-15 dollars.
Compressometer
It's easy to work with. It is enough to unscrew one of the spark plugs and screw in the threaded fitting of the device in its place. There is an option with a rubberized tip, but you will need an assistant to forcefully hold the measuring device in the desired position. The check is done in all cylinders.
The deviation between all readings should not be significantly higher than 10%.
The exact level of standard data can be found in the car's passport. If it differs significantly from empirical measurements, then elimination of this defect is required. For example, for a VAZ 2112 this figure should be 12.6 kgf/cm2.
Operational reasons for consumption
Breakdowns and failures are not the only reasons for increased consumption. They are often visible even to owners or are found during diagnostics by service center specialists. But not all signs can be identified by service station workers at their stands. You have to independently analyze and understand the essence of the process.
Driving style
All drivers have different driving styles. A calm driving style, without jerks and sudden acceleration/braking, is characterized by moderate and sometimes economical fuel consumption.
Winter driving in an all-wheel drive SUV
If the driver often uses sharp pressure on the accelerator, then the car cannot do without unnecessary consumption.
You can “rush” at a traffic light if the engine power allows. But at the same time, the consumption will “explode” to an exorbitant 30 liters for a passenger car. Whether it is worth using this style of behavior on the road, everyone must decide for themselves.
Car class and engine size
It is generally accepted that owners often pay for increased engine capacity with significant fuel consumption. This is a kind of tribute for comfort. A car of the same class, weight and make should have lower consumption, but in practice this formula is not always confirmed.
A massive power plant, in order to obtain results in speed or power, consumes less gasoline than a similar car with a smaller engine.
This is due to the fact that the “small” engine works with a greater load. And accordingly, more fuel will be consumed.
Terrain
The parameter is relevant for hilly and mountainous areas. If the car was initially used in flat terrain, then it had one consumption. When road conditions change (frequent traffic jams, many uphill sections), consumption may change upward.
Automatic transmission
The opinion that automatic transmission increases fuel consumption by 10-15% is often confirmed in practice. In some cases, the “increase in gluttony” can be 1-2 liters per 100 km of travel. Sometimes the difference is almost unnoticeable. It also depends on the machine itself, and not just on its presence. After all, older models with four speeds differ from six-speed automatic transmissions.
Automatic or manual transmission
To save money when driving with such a unit, we can recommend using the overdrive mode when driving outside the city.
OverDrive reduces consumption and helps you maintain speed. During city driving, owner reviews are not so clear. The characteristics of the option are clarified to a greater extent through individual experiments.
Injection systems
The sensitivity of direct injection fuel systems (D4, GDI, etc.) to low-quality gasoline is felt almost from the first days of vehicle operation. Some automakers do not even officially supply cars with a certain engine configuration to Russia. This is justified by the high cost of maintenance and repair when using low-grade fuel.
Fuel injection system
Therefore, when choosing and before purchasing a used foreign car, it is advisable to inquire about its fuel characteristics. A relatively low price for a nice car can result in very expensive repairs.
Fuel quality
Not all gas stations sell the same gasoline. Unfortunately, this fact also affects consumption. 95 may contain an excessive amount of additives. Therefore, the banal conclusion is to fill up with fuel only at proven gas stations. Although the presence of a company logo is not always a sign of quality. You have to trust your own experience.
Season
Beginners should be reminded that when operating a car in winter, the consumption will be higher. This is affected not only by the heat, ice and traffic jams. The machine starts working with an unheated engine, which first consumes an over-enriched mixture. Also, due to cold oil, the properties of which change at low temperatures, the power plant requires a little more power to rotate the shafts.
Four-wheel drive
A car with one drive axle will be more economical.
Fans of all-wheel drive should immediately prepare for increased fuel consumption.
Or, if possible, do not turn on all drive wheels in unreasonable situations.
Additional factors
Consumption may rise slightly due to power taken from the engine when electrical appliances are operating. The list includes an audio system, air conditioning, headlights on, and electric power steering. It is also advisable to change your winter tires on time. Driving on the highway on non-seasonal wheels can also waste fuel. Routine theft also occurs due to incorrectly calibrated meters at gas stations. But this happens more on the periphery or where clients are not valued.
conclusions
Almost any car over time requires more gasoline per 100 kilometers. It is necessary to undertake repairs only when it is economically justified. The high cost of work in this case does not cover the cost of fuel. Therefore, everyone decides for themselves whether it is worth fighting with extra liters.
Service station specialists often face questions from car owners about why their car began to consume a lot of gasoline. Signs and causes of increased fuel consumption can be combined into two functional groups:
The first category is characterized by changes in the geometry of components and mechanisms due to mechanical wear, affecting the direct operation of the car engine. These include power, lubrication, cooling, power and ignition systems.
6 main reasons for increased gas mileage in a car
1. Wear of parts of the crank group
The compression ratio of each cylinder and the volume of the combustion chamber are important geometric parameters of the thermal and economic balance of engine operation.
When the main and connecting rod journals of the crankshaft wear out, the combustion chamber of the engine increases due to an increase in the piston stroke length. Wear of the piston rings reduces the gas pressure in the combustion chamber, thereby reducing their heat transfer.
2. Mechanical wear of power system components
The efficiency of fuel combustion in the combustion chamber depends on several factors. One of the factors for complete combustion of fuel is the correct ratio of fuel and air in the combustible mixture supplied to the engine cylinder. The required ratio of these media is achieved by precise dosing of fuel and supplied air.
When jets wear out in carburetor engines and injectors in engines with injection systems, the balance of air and fuel is disrupted. A clogged air filter also has a negative impact on fuel economy because it reduces the amount of air supplied.
A faulty fuel pump also causes increased fuel consumption, as it affects the accuracy of the injected fuel dosage. in the network of Autopride car service centers, it is carried out with really high quality.
3. Wear of timing components and parts
Wear of the gas distribution system valves, camshaft cams and the size of the thermal gap affects the engine compression ratio, which ultimately affects fuel consumption. Recommended.
4. Ignition system malfunctions
For complete combustion of the fuel-air mixture in the combustion chamber, several conditions must be met. First, the spark that occurs between the electrodes of the spark plug must heat them to the ignition temperature of the fuel. Secondly, the temperature of the walls of the combustion chamber must correspond to the optimal temperature at which normal combustion of fuel is achieved.
An important parameter is the gap between the spark plug electrodes. Another important parameter in the ignition system that affects fuel consumption is the ignition timing. This is due to the fact that the rate of fuel combustion is almost constant, regardless of the crankshaft speed and the current load.
The fuel must ignite at the end of the compression stroke, so the mechanisms that control the injection advance angle must be in good working order.
5. Lubrication system malfunctions
The oil circulating in the engine not only lubricates the rubbing parts, but also cools them. Thus, the oil provides an optimal thermal balance of engine parts, at which they will operate efficiently without loss of mobility and jamming due to overheating. When the mobility of engine parts decreases, the load increases and engine power decreases, which ultimately affects fuel consumption.
An effective filtration system is the key to proper engine operation.
6. Wear of components and parts of the cooling system
The optimal temperature background for the working components of the engine is ensured by the correct operation of the cooling system. If the cooling radiator is damaged, its surface area decreases. In this case, the coolant does not have time to cool to the required temperature. Ultimately, the thermal balance is disrupted, which leads to excessive fuel consumption. A faulty water pump can also cause an increase in temperature.
4 indirect reasons why the car began to “eat” more gasoline
1. Malfunctions of the vehicle's chassis and chassis
2. Wear of transmission components and parts
When the clutch discs wear out, the drive disc slips relative to the driven disc, which reduces the efficiency of the clutch mechanism as a whole. Clutch slipping occurs, which increases the load on the engine and increases fuel consumption.
3. Increased vehicle drag
Luggage carried on the roof of a car increases the drag area when the car is moving. This factor affects fuel consumption as the load on the car engine increases. Driving your vehicle in a headwind also increases your actual fuel consumption.
4. Driving style
It is known that fuel consumption will be effective at steady and constant engine operation without a sharp change in the crankshaft speed. Smoother engine performance can be achieved by preventing unnecessary stops and idling at traffic lights. When driving in icy or rainy conditions, fuel consumption increases as the amount of wheel slip relative to the road increases.
There are cases when a car “eats” much more fuel than stated by the manufacturer. This does not mean that they tried to deceive you.
The point is that when a vehicle is tested, it is tested under almost reference conditions, and that is when the fuel consumption calculation occurs. Exceeding this indicator is often caused by either “aggressive” driving style or inappropriate operation of the car.
Let's highlight the five main reasons why this happens.
Electronics and consumables
If the spark plugs or, for example, the air filter are clogged in a car, then the following happens: the fuel-air mixture does not burn in the engine as it should. Since the mixtures are not enriched with air, the vehicle consumes more fuel. Thus, combustion of the mixture occurs in the combustion chamber. If the spark plugs are worn out or covered with soot, some of the mixture does not burn, but comes out along with the exhaust. In general, this reason can lead to an increase in fuel consumption by more than 20%. And if, for example, there are malfunctions of the air flow sensors, lambda probe and others, then the excess fuel consumption can reach more than 100%.
Tire pressure and wheel alignment
When a vehicle's wheels are at the "wrong" angle, it cannot use what is called "natural" rolling. This slows down the car, so in order to maintain a certain speed, the motor spends more energy. Accordingly, fuel consumption can increase by 10 - 20%. For the same reason, you should always monitor your tire pressure.
Aerodynamics
There is a misconception that driving with the windows open is more economical than using the air conditioning system. At low speeds this is really justified. Up to 40 kilometers per hour, the car is only slightly affected by air resistance. However, at higher speeds this figure increases significantly, and accordingly the engine has to “put in more effort” to overcome the resistance. An air conditioner, on the other hand, requires very little energy.
Engine temperature
An unheated engine leads to additional fuel consumption. This is because the electronics react to a cold engine. The optimal temperature of the power unit is about 90 - 100 degrees Celsius. If this figure is higher, then the electronics will also “dispense” more fuel.
Aggressive driving style
Sharp acceleration and braking lead to fuel consumption of more than 50%.
Why does my car consume a lot of gas? First of all, you need to check the technical nuances.
- Constantly driving with an underheated engine, when the coolant temperature is constantly below normal.
Most often this is a problem with the thermostat. As a rule, in this case it gets stuck in the open position and drives the coolant in a large circle.
- Worn clutch
- Production of cylinder-piston group
- Wear of the crank mechanism
- Wear of the timing mechanism
- Unadjusted valve clearances
- Problems in the fuel system (carburetor, fuel pump, injector)
- Unadjusted wheel alignment, wheel hub bearings that are too tight - poor rolling.
- Low tire pressure.
- Untimely replacement of the oil filter. Air passes through a dirty filter poorly and the mixture turns out to be of poor quality, it does not burn completely and more gasoline is required.
- Incorrect gaps in spark plugs, interruptions in the operation of spark plugs. As a rule, this is a consequence of poor, low-quality gasoline. A characteristic feature is a red coating. Late ignition - the mixture burns inefficiently. An increase in angle of 1 degree increases gas mileage by 1%.
Driving style
Every driver drives differently. The driving style of a vehicle significantly affects the amount of fuel consumed. How to avoid overspending? Several secrets of economical driving are in the article.
About the quality of gasoline...
Compared to European standards, Ukrainian requirements, for example, allow 3 times more sulfur content in gasoline. Sometimes even these figures turn out to be overestimated, which leads to a significant deterioration in fuel quality.
Purchasing gasoline exclusively at branded gas stations does not guarantee quality, since control over intermediaries is insufficient. There are known cases when, after refueling at the gas stations of the largest companies, engines failed. This is rare, but additional precautions will help maintain the performance characteristics of the vehicle's operating components.
Experts recommend changing the oil more often than stated in the technical documentation of car manufacturers. This is due to the fact that increased sulfur content in the fuel leads to a loss of engine oil properties. Because of this, the oil loses the necessary characteristics and unevenly cleans and lubricates the car engine. Deposits remain in the engine, which also affect its performance.
Despite manufacturers' recommendations to refuel with A-92, given the quality of gasoline, it is recommended to use fuel with a higher octane number. It is not advisable to store such gasoline for a long time, since its high properties are achieved with the help of additional additives, which lose their effect over time.
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It's unpleasant to throw money away when your car has high fuel consumption. Those who do not trust their car to a car service try to determine the cause of gasoline consumption on their own. Others, on the contrary, rush to the service station, where the technician begins to examine the car.
Why does the car still consume a lot of gasoline? In fact, increased fuel consumption may be the result of not one, but several problems at once. Let's try to figure out what affects fuel consumption and whether it is possible to reduce fuel consumption without the help of specialists:
1. Errors in the electronic control system
One of the main reasons is a malfunction of the engine management system. This is due to the incorrect operation of the sensors, which are designed for optimal calculation of the air-fuel mixture:
- Temperature sensors (coolant and intake manifold).
- Throttle position sensors (TPS).
- Mass air flow sensor (MAF). Its service life is significantly reduced if the air filter is not changed promptly.
- Oxygen sensor (lambda probe).
Errors in these sensors to varying degrees cause a “lean” or “rich” mixture, which results in loss of power and excessive fuel consumption. All these faults are difficult to determine without diagnosing the car, but it is possible if you look for it by rebuilding the sensors.
2. Abnormal pressure in the fuel system
The pressure in the fuel system may be higher or lower than normal.
It is a rare situation when there is high pressure in the fuel system; the opposite situation most often occurs.
Low pressure in the fuel system causes the engine to lose power. And on a car with an automatic transmission, it increases the operating time of the car at higher speeds and, as a result, increases fuel consumption.
3. Injector malfunction
If the car owner does not monitor the condition of the engine, then over time its efficiency will decrease, and if started, the engine will begin to stall. The reason for this is dirty injectors. The quality of gasoline atomization deteriorates and normal mixture formation is disrupted. In this case, cleaning the injectors will help, which you can easily do yourself.
4. Faulty catalyst
Over time, the catalyst may burn out or even partially collapse. We will not delve into the intricacies of the process, the main idea is: the more “clogged” the catalyst is, the richer the mixture. This in turn causes greater heating of the catalyst, which negatively affects its durability. The consequence of this will be a decrease in engine power and excessive fuel consumption.
In addition, the cause of catalyst destruction may be: dirty injectors, old spark plugs, faults in the control system or low-quality gasoline.
5. Engine temperature
The optimal operating temperature is 98 -103°C. If the engine overheats, the fuel mixture becomes discharged. The car starts to run on a lean mixture, which results in a loss of power.
If the engine is not warmed up, then increased gasoline consumption occurs due to enriched fuel injection (necessary for warming up the internal combustion engine). For example, if the temperature is 80°C or lower, then fuel consumption increases by 20%.
The reason when the engine is not operating at operating temperature lies in the engine cooling system (for example, in the thermostat). Thus, if you use the car only for short distances, when the engine does not have time to warm up enough, hence the increased fuel consumption than for long trips.
6. Dirty air filter
Yes, oddly enough, but one of the reasons when a car eats a lot of gasoline is a clogged air filter. Due to the lack of air in the engine, the effect of “air starvation” begins and the operation of the mass air flow sensor is disrupted. As a result, we again see a picture where mixture formation occurs incorrectly, which causes excessive consumption of gasoline.
Conclusion
Now you know that to eliminate the cause, sometimes it’s enough just to replace the air filter, and sometimes you can’t do without competent diagnostics of the car.
In addition to the above, you can reduce gasoline consumption by changing your driving style or using the air conditioner less often.
Also, do not be surprised if the car “guzzles” fuel when wheels are installed that are significantly larger than those recommended by the factory, or fuels and lubricants of inappropriate viscosity or quality are used.
