High fuel consumption on the VAZ 2107 carburetor - reasons

From the article you will learn about the possible reasons for the increase in fuel consumption of a VAZ 2107 car with a carburetor engine. The reasons for the high fuel consumption of the VAZ 2107 can be divided into those related and unrelated to the operation of the carburetor of the car engine.

Before talking about increased fuel consumption, it is worth determining what is normal for the VAZ 2107.

VAZ 2107 cars in carburetor version were produced with engines of 1.2, 1.3, 1.5 and 1.6 liters. For a 1.5 engine, a consumption of 6.8 liters can be considered good. per 100 kilometers on the highway and 9.6 l./100 km. in the urban cycle. For an Engine with a volume of 1.6 - 6.9 liters and 10.2 liters, respectively. Well, the 1.2 and 1.3 engines are distinguished by better efficiency, although they did not gain popularity due to their low power.

VAZ 2107 fuel consumption per 100 km carburetor

To talk about whether a car consumes a lot of gasoline, you need to know what the consumption should actually be.

Depending on the engine installed on the car, the consumption may be as follows (for more details on the consumption of carburetor cars, see our fuel consumption table for carburetor cars):

The difference is obvious. However, the power of the first engine is 72 hp. , and the second one is 80. That’s why it consumes so much gasoline. However, in the case when there is an increase in consumption above the nominal, it is worth talking about too much fuel consumption.

VAZ 21011

Fuel consumption calculator: calculate fuel consumption

Under this name, the first Zhiguli model appeared at the Volzhsky Automobile Plant. The VAZ 2101 became a pioneer in the family of the most popular domestic cars, enjoying success both among Soviet drivers and abroad. This car rolled off the factory assembly line in 1970, and production of the “penny” continued until 1988, after which it was replaced by new modifications on the same platform.

VAZ 2101 was recognized as “The best domestic car of the 20th century.” Over the entire production period, only one of two engine options was installed on this model: either a 1.2-liter engine with a capacity of 64 hp, or a 1.3-liter power unit with 69 “horses”. Both engines were accompanied by a four-speed manual transmission.

“Zero Eleven” or “Zhiguli-1300” is a modified model of the base VAZ 2101. The changes affected only the appearance (the radiator grille received more vertical bars, “fangs” disappeared from the bumpers and rubber pads appeared, brake lights received reflectors). The VAZ 21011 was equipped exclusively with a 1.3-liter engine with a power rating of 69 hp.

Engine power system

Conventionally, the power supply system can be divided into two elements:

1. Air supply;
2. Fuel supply.

Let's consider the first option. If your car consumes too much gasoline, the problem may lie in a dirty air filter. All drivers should know that without oxygen, fuel combustion is impossible. Fuel consumption should be carried out in a ratio of 1 kg of fuel to 15 kg of air. This parameter is not always present, but should have approximate values.

If the air filter is dirty, it will turn out that fuel combustion will be poor, which means the engine efficiency will decrease, which is the reason why the VAZ 2107 carburetor has high fuel consumption, but there are other reasons, which lie in the operation of the carburetor itself .

If it is not set correctly, the Lada will have an air/fuel mixture that is too rich or too lean. In both cases, it consumes a lot of fuel and noticeably loses power. To get rid of the problem, you need to configure the system correctly. If the VAZ 2107, or more precisely, its carburetor, still consumes a lot of gasoline and has difficulty starting, then you should check the cleanliness of the fine and coarse filters.

Technical features affecting fuel economy

From the functional and technical side, fuel consumption is affected by:

• condition of the cylinder-piston group - when worn, consumption increases by 20-25%,
• coolant temperature – when it decreases relative to the optimum, the overconsumption increases by 8-10%,
• high oil density, especially in winter, when friction in the engine and transmission increases losses,
• clutch slipping,
• a jammed brake caliper and an unadjusted brake system as a whole,
• underinflated tires (a more economical option - slightly overinflated by 0.2 atm.),
• over-tightened wheel hub bearings add another 10-15% to the consumed volume of fuel.

Read more

Consumption can be reduced, but this will affect the dynamics of the car. I did this on a VAZ-2106 with a 2107 carburetor: I replaced the fuel nozzle in the first chamber with 105, and in the second with 146. I set both air jets to 170. I also replaced the accelerator pump nozzle from 0.5 to 0.4.

Ignition system

Diagram of a non-contact ignition system: 1 - non-contact sensor; 2 — ignition distributor sensor; 3 — spark plugs; 4 - switch; 5 - ignition coil; 6 — mounting block; 7 - ignition relay; 8 — ignition switch.

If the carburetor consumes gasoline in nominal quantities, then the problem may be hidden in the ignition system (the correct adjustment of which is discussed in the article on adjusting the ignition on the VAZ 2107). The check should begin with a visual assessment of the vehicle's behavior.

Popping noises in the muffler or detonation at low speeds may indicate poor spark plug performance or incorrect timing. Unscrew the spark plugs and check their color.

Black carbon deposits indicate that the ignition system is misfiring, when fuel is supplied but does not ignite. This indicates that the candle is not working. If all the spark plugs are the same color, then the ignition is late and needs to be adjusted.

The white color of all candles indicates a poor air-fuel mixture when the fuel consumption of a VAZ 2107 with engine 2106 or 03 (carburetor) exceeds 10 liters per 100 km. In this mode, there is early ignition, the engine eats a lot of air, but is forced to burn gasoline to gain the required speed.

Briefly about the technical characteristics of the injection engine

• urban mode - 8.5 l;
• 90 km/h - 6.9 l;
• 120 km/h – 9.2 l.

The use of a new injection system allows you to get rid of the constant adjustments inherent in the carburetor; idle speed is always stable. Dosage occurs using an electronic control unit, which is guided by sensor readings

:

• throttle position;
• crankshaft position;
• oxygen concentration;
• air consumption;
• coolant temperature.

In addition to changes in the electrical circuit of the VAZ 2107i, the following innovations were applied:

• hydraulic chain tensioner;
• hydraulic valve compensators.

These components made the engine quieter and freed the car enthusiast from such an important operation as adjusting the valves.

Driving in neutral gear

Almost all VAZ 2107 cars equipped with a carburetor engine with an economizer have the ability to turn off the fuel supply when releasing gas while in gear, which was not the case with early versions of the Lada. In this connection, there is no need to drive in neutral gear, supposedly to save money.

There are no savings here. When the gearbox is in neutral, the speed drops, and the autonomous idle system comes into play, which, when the throttle is closed, supplies the engine with an additional portion of fuel so that it does not stall. In this mode, the fuel system consumes a lot of gasoline.

Aerodynamics of the car

Many Russian drivers have already noticed that the fifth model has much lower consumption due to its aerodynamic properties. We are talking about a radiator grille that is flush with the hood, and does not stick out, as on the seven. The high “nose” of the grille creates additional air resistance, which leads to excessive fuel consumption. In this case, it is recommended to install the hood and grille from the VAZ 2105.

The second reason is a roof rack that has too much protruding cargo. Tall suitcases, boxes and other items carried on the roof also make it difficult for the vehicle to move, causing the engine to consume much more gas than it should. The best way out of the problem is a trailer that hides behind the car, is lightweight and can hold more cargo than a trunk.

Open windows when driving on the highway also interfere with normal gasoline consumption. If the car is hot, you can use central air ducts, which open at speed and set the flow of cold air, which is much more convenient and economical.

Technical features affecting fuel economy

From the functional and technical side, fuel consumption is affected by:

• condition of the cylinder-piston group - when worn, consumption increases by 20-25%,
• coolant temperature – when it decreases relative to the optimum, the overconsumption increases by 8-10%,
• high oil density, especially in winter, when friction in the engine and transmission increases losses,
• clutch slipping,
• a jammed brake caliper and an unadjusted brake system as a whole,
• underinflated tires (a more economical option - slightly overinflated by 0.2 atm.),
• over-tightened wheel hub bearings add another 10-15% to the consumed volume of fuel.

Read more

Consumption can be reduced, but this will affect the dynamics of the car.

Aggressive driving style

Many car owners push their Lada into too high speeds in order to shift to a higher gear. The classic engine is not designed for this driving style. It is designed for a quiet ride, since the car is not sporty and does not tolerate high speeds.

The optimal shift mode should be in the range from 2500 to 3000 rpm. If you turn the engine up to 3500, then in addition to increased consumption, you can also get a decrease in the resource of the power plant.

Tire pressure

The last reason is one of the most common - low tire pressure. To make it clearer, just lower the wheels of the car and try to push it. Everyone knows that this will be extremely difficult.

The same situation occurs with the engine when it tries to move a car with flat tires. It has to expend more energy, which means it needs more fuel.

Now it’s clear why the VAZ 2107 carburetor has high fuel consumption. The reasons for this phenomenon can be easily eliminated and will not require large expenses. It is enough to monitor the condition of your car.

Reasons not related to the carburetor

Engine malfunctions

Watch and listen to how your car's engine works. The presence of black or bluish smoke, rattling sounds are signs of a problem. In order to figure out what is wrong with the engine, it is worth measuring the compression in the engine cylinders. It is recommended to carry out this operation even if you are satisfied with the engine performance, but the fuel consumption is not. To do this you will need a device - a compression meter.

Compressometer

To obtain correct results, compression is measured on a warm engine. Unscrew all spark plugs. The contact of the central wire of the distributor is placed at a distance of 1-2 cm from the ground. The compression meter is pressed against the spark plug hole, and an assistant, fully pressing the gas pedal, turns the engine with the starter; 3-4 seconds is enough to get results. The operation is performed for each cylinder and the results are recorded. The permissible difference in pressure between the cylinders should not exceed 1 kg/cm². And the compression in each cylinder must be at least 9.7 kg/cm². If the readings are not within the normal range, this indicates an engine malfunction; it is necessary to understand the reasons, and repairs may be required. You should not rely on the efficiency of a faulty engine.

Violation of engine thermal conditions

Temperature sensor VAZ 2107

The operating temperature of the VAZ 2107 engine is 80-90 degrees. If the thermostat of the cooling system is constantly open, the liquid will move around a large cooling circle, and this in turn will lead to incomplete warming up of the engine, loss of power and increased fuel consumption. And the opposite situation occurs: when the engine overheats, the filling of the cylinders with the fuel mixture is disrupted, which leads to loss of power and increased fuel consumption.

Incorrect ignition timing setting

It is not for nothing that the manufacturer indicates the recommended ignition timing (IAF) in the car manual, since it ensures that the engine operates in optimal mode. Deviations of the OZ in one direction or another will lead to an increase in fuel consumption. For VAZ 2107, the SOP should be 5° for AI-92 gasoline. But it should be noted that the best way to set the ignition timing is on the road. The engine warms up to operating temperature. The car accelerates to 50 km/h, and in the last direct gear the gas pedal is sharply pressed. You should hear a detonation sound (tapping of fingers) that ends after a few seconds. If the detonation is prolonged, the ignition is too early; if there is no detonation, the ignition is too late. The SOP is adjusted by rotating the distributor.

Distributor VAZ 2107

Damaged or leaking connections in the fuel line

Fuel leak

Everything is simple here, if the tightness of the tank, hoses, loose clamps of various connections is broken, fuel may leak. Having placed the car in the inspection hole and started the engine, you must carefully inspect the entire length of the fuel line for leaks, including under the hood. For convenience, it is advisable to remove the air filter. If necessary, tighten the clamps, change the hoses or gaskets.

Incomplete release of the car wheels

A very common situation. Braking a wheel or wheels creates resistance to vehicle movement and, of course, increases fuel consumption. The probable reason for this situation is the lack of free play of the brake pedal, that is, the wheels are constantly in a state of slight braking. On the VAZ 2107 the free play is 3-5 mm. adjustable by moving the brake light switch.

Brake pedal VAZ 2107

A seized caliper piston could also be a possible cause. We pay attention to the brake discs; with constant contact, dark marks from the pads remain on them, and the car disc can become very hot. Check to see if the handbrake cable is overtightened.

Wheel bearings overtightened

If the hub nuts are tightened too much, additional resistance will be created to the vehicle's movement, which will affect fuel consumption.

Insufficient tire pressure, tire wear

Both on the VAZ 2107 carburetor and on other cars, high fuel consumption can be caused due to low tire pressure. It must be monitored once a week and before each long trip. Low tire pressure prevents the car from rolling. You can check the pressure with a pressure gauge.

Pressure gauge

Violation of wheel alignment angles

Incorrect angles of the front wheels of the VAZ 2107 not only create additional resistance to movement and increase consumption, but also lead to increased tire wear. Work on checking and setting the wheel angles of the car is carried out after each replacement or repair of suspension parts. This operation is also carried out after strong impacts due to careless driving.

Defective spark plugs

They lead to interruptions in engine operation, loss of power, and increase fuel consumption.

Malfunction of the vacuum ignition timing regulator

It will cause an incorrect shift in the ignition timing at different engine operating modes, this will lead to a loss of power, throttle response and, as a consequence, increased gasoline consumption.

Vacuum corrector VAZ 2107

Improper adjustment of the clutch drive, or its malfunction

With such a problem with the car, slippage occurs, difficulty accelerating the car, which inevitably leads to excessive gas, which will significantly increase the appetite of your vehicle.

Driving style

High fuel consumption of a VAZ 2107 carburetor may be a consequence of a driving style that can quite significantly affect fuel consumption. It’s one thing when you are calmly driving a car and quite another when you are trying to squeeze out of the engine everything that it is capable of using the gas pedal. An aggressive driving style increases fuel consumption.

Vehicle overload

Everything is logical here. More weight means more load means higher consumption.

Fuel quality

When refueling with low-quality fuel, you will have to press the gas pedal harder, and this will lead to an increase in fuel consumption. Low-quality fuel can have a detrimental effect on a car's engine, so be careful what you put into the tank.

Air filter dirty

Dirty air filter

The composition of the fuel mixture formed by the carburetor greatly depends on the amount of incoming air. When the air filter is dirty, the air flows worse, the engine loses power, we use the gas pedal more actively, and consumption increases.