Gasoline pump "Gazelle": repair and maintenance

Zavolzhsky Motor Plant is the main supplier of engines for cars "Volga" and "Gazel". The motors of this enterprise have long been known to Russian motorists and motor technicians. Good maintainability, simplicity of design and reliability of the main systems deservedly put these engines among the best domestic motors. In addition, in the late 90-ies of the twentieth century, the plant designed and installed a distributed injection system for these engines. These motors, in particular, ZMZ-405, are installed on low-tonnage trucks "Gazelle", minibuses "Sable" and their modifications.

Of course, the injection system complicated work and repairs, but maintenance of the engines does not raise any special questions. The same can be said about the repair of the fuel system of cars "Gazelle" and "Sable".

Power Supply System

Its scheme for almost all engines with a fuel injection system is structurally the same. It consists of a tank with a module, a pump, highways, a ramp and injectors. The auxiliary systems include a gasoline tank ventilation system, a fuel backflow , a fuel level sensor . In the carburetor system, a ramp with injectors is excluded from the circuit and a carburetor is added. The power supply system is also equipped with a system for backing the fuel into the tank with the engine stopped.

Location of the gas pump "Gazelle"

The principal difference between a carburetor and an injection system is the location of the pump. On the carburetor unit, it is located on the engine. The unit is equipped with a mechanical drive from the camshaft. On the injection modification, the element is installed directly in the tank and has an electric drive. How is the gasoline pump "Gazelle" fed? Connection to the electrical system is carried out together with the switching of the fuel level sensor. The design is presented in the form of a pair of connectors, which are located on the gas tank. The pump system generates considerable pressure, so the fuel reaches the nozzles at high speed. This is part of the technological process of fuel injection. So fuel is better mixed with air before feeding into the cylinders.

Pump unit

The diaphragm element on the carburetor models pumps gasoline through vacuum, which is created by a special gas-resistant diaphragm. On the injection motors, as already mentioned above, the pump is installed directly in the tank. The element is connected to a coarse filter and a fuel level sensor. Structurally, it is a vibrating electric pump in which a moving armature pumps fuel. This option is considered much more reliable, as it does not suffer from the main disadvantage of gasoline pumps of carburetor engines - overheating in hot weather and reduced productivity. It is the high-quality and stable operation of the element that is the basis for the correct operation of the engine, which depends entirely on the amount and brand of the mixture.

Filter Features

The fuel that enters the engine is cleaned through two elements. The first (clarifier-settler) is located next to the gas tank. It detains in itself large rubbish, dirt and water, which is collected in a special removable glass at the bottom. The fine filter is installed in the hose rupture in front of the carburettor. It is designed to delay smaller dirt particles: the fuel passes through a special cardboard enclosed in a plastic cylinder.

On injection engines, the fuel is cleaned through a filter located on the intake pipe of the pump. It is a thin flat metal mesh. It effectively detains dirt and debris caught in the fuel tank.

Troubleshooting

So, what if the petrol pump does not work? "Gazelle" in this case needs to be diagnosed. It should be noted that the most common problem is insufficient fuel pressure. It is very harmful for fuel injectors. For this reason they fail. The first sign of a malfunction is jerks when driving a car. The reasons for this can be both low pressure in the fuel rail, and uneven operation of the pump. Another disturbing manifestation is the difficulty of starting the engine. Injection engines are distinguished by an easy start. In the event of interruptions in the operation of the gasoline pump, the engine is started from the second or third attempt. It is not good. Check how the gasoline pump "Gazel 405" can be used with a special indicator for the injection engine. The diagnosis itself is quite simple - everything is indicated in the instructions to the indicator. If the electrical circuit is faulty, the engine will not start. You should start troubleshooting by checking fuses, relays and wiring.

Differences in diagnosis of the diaphragm element

Since carburetor gasoline pump "Gazelle" ZMZ-402 has a mechanical drive, there is no electrical component in it. A breakdown of this type of pump usually results in rupture or damage to the diaphragm. Because of this, the fluid pressure decreases, in the worst case - its supply is completely stopped. Replacement of the diaphragm is not a problem.

Checking the gasoline pump with a pressure gauge

Also, the work and the performance of the mechanism can be checked using a special manometer. It is connected to the fuel rail and measures the pressure created by the pump in the system. When the ignition is switched on, the gasoline pump will start working immediately. "Gazelle" is not mandatory. The pressure gauge will relieve the pressure reading. Ideally, it should be 300-380 kPa. After this, it is necessary to turn off the manometer and ride along the usual road with acceleration and braking - a standard test drive. After that, we again measure the pressure. If it differs from the original measurements, the mechanism is defective or its resource is close to completion. Can I recover it? We will describe this below.

Repair of gasoline pump "Gazelle"

On carburetor engines the gasoline pump is removed quite simply. To do this, the fuel hoses are disconnected, the nuts securing the pump flange to the cylinder head are loosened. In addition, for repair it is not necessary to dismantle the whole mechanism. To replace the diaphragm, it is sufficient to remove only the upper hemispherical part. Repair of gasoline pump "Gazelle" with the injection system is impossible - it must be completely replaced. To remove the element, it is required to unscrew the flange ring from the fuel tank, reduce the pressure in the fuel system, disconnect the wires and remove the glass together with the fuel level sensor. All this looks like this:

The pump stays on the latches and is removed from the housing together with a filter, which will also replace it wisely. On sale is as a complete set consisting of a submerged glass with a filter and a fuel level sensor, and a separate gasoline pump. At the "Gazelle" its price is 1-2 thousand rubles. Full set - up to 4 thousand. As for the element for carburetor models, its price in the collection fluctuates around 1 thousand rubles.

Conclusion

Diagnosis and repair of gasoline pump "Gazelle" - a simple work that almost any motorist can do, who understands the principles of operation and features of the device. A minimum set of tools is required for replacement.