Cause of too much fuel consumption - undirbúningur fyrir endurnýjun hreyfilsins, gírkassa og annarra tækja

Cause of too much fuel consumption

Every driver wonders how he can optimize the cost of using a car. The biggest cost of operating a vehicle is fuel consumption. I do not know if you know that with the consumption of 7 liters of fuel per 100 km, and the annual covering of 20,000 km, the expenses you will incur for fuel alone are about PLN 7,000 per year. After 5 years, the amount increases to PLN 35,000. The price of a liter of fuel at the level of PLN 5 was used for estimation – with a higher fuel price, the costs will increase even more.

These are not small costs, so it’s worth checking how much your car burns and finding out how you can reduce fuel consumption. Also remember that burning too much fuel is often a signal that something disturbing is happening to your vehicle. It is worth going to a mechanic for computer diagnostics and verification of the technical condition of elements that are most often responsible for inflated fuel consumption – we write about these elements in more detail later in the article.

Before you start analyzing whether you have inflated fuel consumption – a small but important note. When assessing the fuel consumption of your car, do not refer to the fuel consumption that the manufacturer has provided in the technical data of the vehicles. It is underestimated by about 30% in relation to the fuel consumption that we will achieve in real conditions. The reference point here may be information obtained from other vehicle users. On the Internet, we can easily find this type of real reports of fuel consumption of specific vehicle models and engine versions (we recommend motostat and autocentrum reports).

How to calculate the combustion of a car?

Almost every modern car is equipped with a digital fuel consumption display, which based on the injection times gives the approximate fuel consumption in the car. However, these are only approximate data, calculated by the car’s on-board computer (ECU).

The method illustrating the most realistic level of fuel consumption is empirical measurements.


Go to the station and refuel fully (to “bounce” the distributor gun). Write down the mileage. For example, the car had a mileage of 145,000 km.


Use the fuel almost to the end, go to the station and refuel the car to full again (to “bounce” the distributor gun). Re-write down the mileage of the vehicle and the amount of fuel refueled. For example, the car had 145,700 km and 35 liters of fuel “entered” the tank.


Then the amount of fuel consumed – that is, 35 divide by the distance covered, i.e. 700 km (145,700 km – 145,000 km) and multiply by 100.

(35 / 700) * 100 = 5 liters of fuel.

This is the average fuel consumption over a distance of 700 km.

Ifyour measurements – calculating fuel consumption shows inflated fuel consumptionand, you will certainly find below some practical tips that will help you locate the cause of too much fuel consumption, and consequently help reduce fuel consumption.

Why does the car burn too much fuel?

The most common reasons for too much fuel consumption are:

1. Technical defects of the vehicle

The technical condition of the vehicle is a very broad issue, so we will focus on the elements that most often “increase” fuel consumption. What most often contributes to too much fuel consumption?

Faulty thermostat

A cold engine sometimes needs even a dozen or so minutes to fully heat up – especially in winter. As standard, the engine is cooled by a radiator. To accelerate the heating of the cold engine, the thermostat closes the supply to the radiator so that the coolant circulates in a short circuit, and is not additionally cooled by the radiator. This helps to quickly get a warm air supply and heat the engine faster.

When the coolant reaches the right temperature, the thermostat opens the supply to the radiator, i.e. the so-called radiator. large circulation to prevent overheating of the engine.


A faulty thermostat can significantly increase fuel consumption and prolong engine warm-up. A malfunctioning thermostat often locks in a position where it is fully open. As a consequence, the engine that is just warming up is additionally – immediately cooled by the radiator. This significantly extends the warm-up time of the cold engine, which in turn significantly increases fuel consumption, because with a cold engine in order to stabilize its operation, the computer significantly increases the doses of fuel administered. In extreme cases, having a faulty thermostat and overcoming short distances, fuel consumption can increase by up to 30%.

Damaged fuel injections

Fuel injectors are a very sensitive element to fuel quality. The fuel is properly dosed by injectors, and injected into the cylinders under high pressure reaching in the case of diesel engines up to 1800 bar (Common-rail injections). In addition, the fuel cools the injectors. To be aware of the hard work done by the injector, just enter the numbers. Approximately 600 injections per minute are made by 1 injector with a calm ride (engine revolutions ~ 2300 rpm). Translating this into a real route during the trip from Warsaw to Gdynia, each injector will perform about 162,000 fuel injections. This is why refueling only at branded service stations is so important.

fuel injectors

Fuel injections are a very sensitive element to fuel quality. Faulty fuel injections can significantly increase fuel consumption.

What is the consumption of fuel injections?
Most often, in addition to increased fuel, there is uneven engine operation, a decrease in power, noisy operation of a cold engine (somewhat quiets down with warming up), a problem with the morning engine start. To protect the injectors against the deposition of sludge in them , it is worth using an effective fuel additive – Ceramizer with cleaning properties of the fuel supply system and injectors – every 10,000 km. This will protect injectors from their damage in the future, and often save several thousand zlotys on their repair.

Lambda sensor

A lambda sensor is a small sensor that is installed in the exhaust system. This sensor measures the composition of exhaust gases, which allows you to assess the current composition of the fuel-air mixture. Under ideal conditions, the engine should draw 14.7 kg of air per 1 kg of fuel. If the composition of the exhaust gas is “too rich” then the computer will transmit information to the injectors to reduce the amount of fuel supplied. Conversely, if the composition of the exhaust gases is “too poor”, then the computer will transmit information to the fuel injectors to increase the doses of fuel administered.

lambda sensor

The lambda probe has a service life of about 50-80 thousand. Miles

Failure of the lambda sensor results in the lack or incorrect information that the engine computer (ECU) receives about the composition of the exhaust gases. As a consequence , the engine often runs in emergency mode, which translates into significantly increased fuel consumption.

Faulty sensors: flow meter (MAF), intake temperature sensor, MAP sensor

These sensors measure parameters important for the combustion of the fuel-air mixture. The flow meter measures how much air enters through the intake system and this is one of the basic factors affecting the setting of the composition of the mixture and the amount of fuel injected.

Flow meter

Faulty flow meter contributes to increased fuel consumption

The air temperature sensor in the bottom, in turn, tells you what the air temperature is. The air temperature affects its density – the lower the air temperature, the higher the air density, to which the computer must adjust the dosage of fuel injections. Therefore, the efficiency of this sensor is also important for the correct level of fuel combustion. Map sensor, in turn, tells about the pressure in the intake system. All these 3 sensors must be fully operational and their failure will affect the increased fuel consumption.

Too low tire pressure

Too low tire pressure causes increased friction resistance and increased fuel consumption. These are not “spectacular” values, but it is an element affecting not only fuel consumption but also driving safety. In road tests, reducing tire pressure by 0.6 bar (from 2.2 to 1.6 bar) increased fuel consumption by 4% and reduced tire life by 30-40%.

wheel pressure

Air conditioning – noticeably increases fuel consumption

Air conditioning is a fantastic device that improves driving comfort, but you should be aware of the fact that this comfort costs money. Enabled air conditioning in summer, depending on the outside temperature (the hotter the conditions, the higher the fuel consumption with air conditioning) in urban conditions increases fuel consumption from ~ 0.5 to 1 liter per 100 km. Interestingly, on the road, the impact of air conditioning on fuel consumption is much smaller, fuel consumption increases on average from 0.1 to 0.3 l per 100 km.

Filters, candles

Remember to regularly change the engine oil, air filter and spark plugs. Interestingly, these are not the elements that are most often responsible for increased fuel consumption – despite the common opinion that this is the case. Replace filters, oils and candles not only because of the impact of these elements on fuel consumption, but above all because of the durability of the power unit.

2. Lack of knowledge of the basic principles of economical driving

Yes, we know that eco-driving is associated by some with an elderly gentleman who on Sundays goes out on the road and blocks the lane of the road driving 30 km / h. However, it is worth drawing the most useful principles of eco-driving to reduce fuel consumption and apply them in your practice of driving a vehicle.

Using navigation or listening to traffic messages on the radio or CB radio often avoids driving in traffic jams and chooses the optimal route to avoid congestion. Avoid nervous situations on the road. They usually provoke you to press the gas pedal hard. Try to be a polite driver, and everyone will benefit from it:)

When accelerating, do not press the gas pedal to the floor when the situation does not require it. Often there is not much difference (apart from fuel burning) between pressing the gas pedal in 3/4 and in 4/4 (maximum). Do not warm up the car at a standstill. The most economical with a cold engine is to warm it up while driving. Almost immediately after starting the engine, hit the road.

Your car burns the most fuel during alternating, frequent rapid acceleration and braking. So avoid the so-called. “torn” driving, i.e. sudden acceleration and braking.

These are just some of the practical principles of eco-driving.

We will describe more about eco-driving in a separate article.

How to reduce fuel consumption?

First of all – bring the car to proper technical condition, verify whether any of the defects described above most often responsible for excessive fuel consumption do not bother your car. Secondly, drive “with your head”, avoid torn driving, check before setting off on the road where there are traffic jams (navigation will help in this, e.g. google maps). Learn the principles of ecodriving – and apply the ones that you think are the most practical. Throw unnecessary things out of the trunk. It is also worth disassembling the roof rack if you are not currently using it. The air resistance that the car has to overcome will be less, and thus the combustion will decrease a little. Use air conditioning and any power devices (e.g. seat heating) with caution.

Use effective fuel additives

It is worth using effective fuel additives every 10,000 km or so. These products clean the combustion chamber and injectors from carbon deposits, and thus prevent expensive regeneration of injectors (the expense of injector regeneration is up to PLN 3-4 thousand).

Faulty injectors – injection No. 5 presents the correct fuel injection stream

Gasoline additives cleaning the fuel system remove impurities from the combustion chamber and injector tips, thus reducing excessive fuel consumption. The Ceramizer petrol diesel additive is an effective, safe and proven product that has been available for sale for over 15 years.

Additive for gasoline Ceramizer CP

An additive to gasoline for cleaning injections will help you in the fight against excessive fuel burning.

Effective oil additives

Another product in the Ceramizer product range is Ceramizer for engine oil. It is a product that creates a ceramic-metal layer on the metal friction surfaces of the engine, and thus fills the worn surfaces and regenerates the engine. This product in many cases can reduce the level of oil intake – as a result of regeneration of piston rings, and its effectiveness is evidenced by over 240 pages of positive opinions. The oil ceramizer equalizes the compression pressure and thus optimizes fuel consumption.

If you notice that your car is consuming too much fuel, it should be a warning light to check the technical condition of the vehicle. Do not assume that it will pass by itself. Money escapes with fuel. Check the technical condition of the elements that are most often responsible for excessive fuel consumption, implement the basic and practical principles of eco-driving and use every 10,000 km an appropriate additive for gasoline, diesel that will clean the combustion chamber and injections, as well as ensure effective combustion of the fuel-air mixture and thus optimize fuel consumption.

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