In addition to the fuel pump, a fuel accumulator is built into the fuel supply line. Its main function is to maintain pressure in the line for some time after the engine has stopped. This prevents vapor lock and improves hot engine starting. In addition, the fuel accumulator acts as a pressure damper to reduce fluid pressure pulsations in the fuel line as a result of the opening and closing of the injectors. The gasoline non-separable filter is installed close to the battery, below the fuel pump. It prevents dirt and insoluble sediments from entering the power system.
The fuel distributor assembly performs the function of a fuel gauge. It mechanically regulates the amount of fuel reaching the injectors. Operation is based on the deflection of the air flow meter sensor. The main fuel is an air mixture under the control of the electronic control unit (ECU) adjustable dynamically by means of an electromechanical pressure regulator. With it, the quality of the mixture can be precisely controlled by signals from sensors on and off the engine. The result of the system is a better combustion of the mixture and an increase in engine efficiency, as well as a reduction in harmful emissions into the atmosphere. Since the accuracy of the fuel gauge is highly dependent on the fuel supply pressure, the fuel system is equipped with a pre-fuel pressure regulator that controls the fuel supply to the distributor assembly. Additionally, differential pressure valves in the distributor assembly ensure that the fuel supply to the metering slots remains constant under all operating conditions. Efficient starting of the engine at low ambient temperatures is ensured by a cold start valve and an auxiliary air valve. The cold start valve is an electrical injector mounted on the intake manifold that injects additional fuel into the intake air stream and enriches the mixture. A time delay thermal switch regulates the opening time of the cold start valve. The auxiliary air valve allows air to be supplied behind the throttle, thereby increasing the speed xx. The built-in bimetallic plate and heater coil determine both the opening amount and the valve opening time. The auxiliary air valve is only active when starting a cold engine and when warming up.
Later modifications are equipped with an idle spool valve. This assembly replaces the secondary air valve and is controlled electronically by the ECU. It ensures the constancy of the speed x.x. under all operating conditions, including increased speed x.x. during warm-up and speed x.x. under load, such as power steering or air conditioning.
Models equipped with a catalytic converter have a feedback power system. This is achieved by processing the signal from the oxygen sensor (lambda probe), built into the exhaust system, and maintaining the optimal ratio of the fuel-air mixture.
Precautionary measures
Many of the operations described in this chapter involve disconnecting fuel lines, which may cause some gasoline to leak out. Before starting work, carefully read the warnings in section "Safety first!", and follow them strictly.
Residual pressure in the fuel lines remains long after the vehicle has been used. Therefore, special care must be taken before disconnecting any part of the power system.
Loosen the connections in the fuel lines slowly to avoid sudden opening which may cause gasoline spills - refer to paragraph 2 for details on how to proceed.
For personal and equipment safety, many of the procedures in this chapter involve disconnecting the negative battery terminal. Firstly, it reduces the risk of electric shock when working with car parts and, secondly, it prevents damage to electronic parts (such as sensors, actuators, ECUs, which are particularly sensitive to power loss when they are in the active position.
Warning: Gasoline is a very dangerous and volatile liquid, so no precautions should be taken when handling it. Keep rooms well ventilated when working with gasoline - open windows and doors to create a draft. Do not smoke and keep open flames or uncovered lamps near the work area. Be aware that household appliances such as heaters, water heaters, and hair dryers also pose a potential gasoline fire hazard. Always have fire extinguishing equipment on hand and familiarize yourself with the rules for their use before starting work. Protect your eyes when working on the power system and immediately wash off any gasoline that comes into contact with your skin with soap and plenty of water. Remember that gasoline vapors are just as dangerous as liquid gasoline; the canister from which the gasoline is drained contains gasoline vapors and is potentially dangerous.
Caution: Pay special attention to cleanliness when working with parts of the power system - dirt entering the power system can block the pipelines, which will lead to engine interruptions.