Diagnostics, repair and replacement of the fuel pump on carburetor and injection VAZ 2108/2109

Print this article Font size 16

If the fuel pump on a VAZ 2109 malfunctions, the fuel supply to the carburetor is completely or partially stopped. Therefore, it is not possible to start the engine cold or hot. It will start at first, but then immediately die. Plus, instability at idle is often observed.

Before changing the fuel pump, it is recommended to first check the condition of the device. It is not uncommon for a breakdown to be corrected with minor repairs.

What fuel pumps were installed on VAZ 2108/2109 cars

Most VAZ 2108/2109 cars were equipped with gasoline engines with carburetor injection of a combustible mixture into the combustion chambers. Only their latest modifications were equipped with fuel injection systems.

Table: serial engines of VAZ 2108/2109 cars

Absolutely all carburetor “eights” and “nines” were equipped with DAAZ mechanical fuel pumps produced by the Dimitrovgrad Automotive Accessory Plant. They were and are now produced under catalog number 2108–1106010.

Mechanical fuel pump DAAZ 2108–1106010

VAZ 2108/2109 injection engines were equipped with electric submersible gasoline pumps produced by Russian enterprises Pekar, Utes, SAAZ, as well as pumps of joint and foreign production. Fuel pumps were installed on the latest modifications. The catalog number of the submersible electric fuel pump VAZ 2108/2109 is 2112–1139009.

Electric pump "Bosch" 2112–1139009

Malfunctions of VAZ 21099 - the injector also fails!

Regardless of the time of year outside, very often the car may simply stop starting, or begin to respond poorly to the gas pedal. In this case, all on-board computer sensors may not show errors. The causes of failure should be sought in the injector.

Usually the breakdown is associated with clogging of the fuel injector nozzles, which increases fuel consumption in the car and reduces traction. Due to the fact that the fuel does not enter in the quantity required for engine operation, the idle speed begins to float. For a VAZ, the normal value when the engine is idling in warm weather is 900 rpm. When starting in the cold season, the engine produces 1500 rpm; with proper operation, after 5–10 minutes they should drop to 900.

It is also worth paying attention to the throttle valve of the intake manifold - over time, black deposits appear on it, which prevents it from properly passing air. It is enough to clean the damper with a special spray and gently wipe with a cloth - the problem is eliminated!

Features of the design and location of fuel pumps VAZ 2108/2109

The DAAZ gasoline pump has a simple mechanical design. It includes:

• a body consisting of an upper and lower part;
• lid;
• mesh filter;
• valves (inlet and outlet);
• diaphragms (3 pcs) with spacers;
• the rod to which the diaphragms are attached;
• return spring;
• manual pumping lever.

  
  Design of the DAAZ fuel pump

The VAZ 2108/2108 mechanical fuel pump is located in the engine compartment of the car and is installed on the auxiliary drive housing (in front of the ignition distributor). It is driven by the camshaft through a cam mechanism and a rod (pushrod). The camshaft rotates an eccentric, which transmits force through a pusher to a balancer at the bottom of the pump housing. The latter raises and lowers the rod with the diaphragms. Thus, a vacuum is formed at the pump inlet, and pressure is formed at the outlet. Valves located in the device body are responsible for its maintenance.

The VAZ 2108/2109 mechanical fuel pump is located on the auxiliary drive housing

On injection VAZ 2108/2109, the fuel pump is not a separate device, but an element of the fuel module. It also includes:

• plastic storage cup;
• coarse mesh filter;
• fuel level sensor.

  
  Fuel module assembly

The module is located in the car tank. Its lid (base) is located at the top of the container. You will find it by removing the back seat and peeling back the carpet.

The electric fuel pump in the injection VAZ 2108/2109 is located in the car tank

Structurally, the fuel injection pump VAZ 2108/2109 is an electric motor with an impeller on the shaft, which, rotating, pumps gasoline, creating a vacuum at the inlet fitting and pressure at the outlet. The pump is powered from the machine’s on-board network, protected by separate relays and a fuse.

Design of the electric fuel pump VAZ 2108/2109

An article dedicated to self-repair and replacement of the gas tank on a VAZ 2109 is located here:

Disassembling and replacing the fuel pump

So, now we’ll tell you specifically about how to properly disassemble, replace damaged elements of the fuel pump, or completely replace this device with a new one.

Hatch

1. In any case, we recommend purchasing a repair kit. It doesn't cost much. But there is no need to rush into buying a fuel pump. Who knows, maybe a simple repair will bring the pump back to life.
2. Remove the air filter along with its housing.
3. Disconnect the fuel supply and return hoses from the fuel pump fittings.
4. Unscrew the mounting nuts that hold the pump itself.
5. Carefully remove the pump, being careful not to damage the gaskets.
6. Inspect the pump parts for cracks or damage. Check the fuel pump valves for leaks and perform all the operations we described above.
7. Assess the current condition of the suction and discharge fittings. When dismantling, they must remain motionless in their seats. They break extremely rarely, but nothing should be ruled out.
8. Check the fuel pump diaphragm. The presence of ruptures and peelings indicates that it must be replaced.
9. Look at the current filter. Damage and excessive contamination are clear signs of wear and warrant replacement.
10. Treat the filter components with clean gasoline and blow with compressed air using a compressor.
11. If you find damaged elements, replace them with new ones using a repair kit.
12. Replace the pump gaskets if necessary.
13. When installing new gaskets, be sure to first treat their surface with Litol 24.
14. If the pump housing itself is damaged or there are other serious problems, you will have to completely replace the fuel pump. Repairs won't help him.
15. Next, when partial repairs are completed or you decide to take a completely new pump, it’s time for reassembly.
16. Be sure to adjust the feed using shims of the required thickness so that the pusher output has an optimal indicator. We talked about this above.
17. If the pushrod protrudes too much, it will cause the fuel pressure to be too high, causing your carburetor check valve to break.
18. If the distance is less than required, as the load increases and the vehicle speed increases, the engine will not be able to receive enough fuel.
19. Reassemble by following the reverse sequence of dismantling the fuel pump.
20. Make sure the arrow on the body points towards the carburetor.
21. When installing the diaphragm pump assembly, the holes in the gasket are located away from the muffler pipe.

Well, you figured out how you can repair and replace the fuel pump yourself. The task is really not difficult, although this unit plays a very important role in the performance of the entire VAZ 2109 car.

Checking the pump characteristics

As you can see, the main reasons for a non-working fuel pump are valves, filters, hoses, and diaphragms. At the outlet we get insufficient pressure. How to measure this pressure, and within what limits is the norm? Firstly, you need to know exactly the nameplate value of the output pressure to the carburetor of your car at idle speed. Approximately the indicator should vary from 0.2 to 0.35 atm.

Measurements are carried out using a pressure gauge with a division value of 1.6 atmospheres. If the pressure is not much less than normal, replacing individual parts may help solve the problem. But if there is a significant deviation, the VAZ 2109 fuel pump will most likely need to be replaced. Timely maintenance and rational use help to avoid this.

In addition to the pressure indicator, in order to repair a part, you should know the characteristics of the pump itself. If the linear parameters have changed, the tightness and stability of the entire mechanism may be impaired.

The rod must have a length of 82.4 mm and protrude above the gasket by no less than 0.8 mm and no more than 1.3 mm. The thickness of the closest gasket is 0.3 mm. The stroke of the rod should be in the range from 2.5 to 2.8 mm.

Checking the pump's functionality

It is easy to check the VAZ 2109 fuel pump even without special instruments. The injector will not be able to operate without pressure in the fuel rail. Therefore, you need to keep the pump motor spinning. It’s easy to check; just connect its terminals to the battery. If you are afraid, then turn on an incandescent lamp in the gap of one wire. It will help determine the health of the motor winding. Please note that the filter must be as clean as possible. If it is clogged, be sure to change it. Otherwise, the pump will not be able to create the required pressure.

Repair of VAZ 21099 injector

In most cases, you can get by by simply cleaning the injector. This procedure can be done at every car service center. To prevent serious damage, have your car diagnosed in a timely manner. You can do the cleaning yourself using chemicals, but it will not be complete. If you decide to clean the injector yourself, you need to buy a repair kit for rubber O-rings for injectors and injector cleaning fluid.

Before performing this procedure, you need to remove the terminals on the battery and disconnect all power supply connectors near the injector. Then we proceed to remove the manifold, carefully unscrew and disconnect the pipes from it. After this, we release the pressure in the fuel rail of the injector by pressing the nipple on the left side of the rail.

Next, carefully move the sealing clamps from the injectors and, by swaying in different directions, remove our injector. It is not difficult to see whether the injectors are dirty. After disconnecting each nozzle, place them in a jar with a pre-prepared chemical mixture for 30–40 minutes. Once you have completed this procedure, we proceed to reassemble our fuel system in reverse order. Be sure to remember to change the o-rings on the injectors that come in the repair kit.

VAZ 2109 fuel pump malfunction, types of VAZ gasoline pumps

On a VAZ 2109, signs of a fuel pump malfunction are a complete or partial cessation of the supply of gasoline to the carburetor, this entails the inability to start both a cold and hot engine, it will start and stall, in addition, unstable idling is possible. If you suspect that the fuel pump in the VAZ 2109 is not working, then you should check it. It's not difficult to do it yourself, just read this article.