Contents: Petrol models ↡ Diesel models ↡ Safety precautions and rules for…↡ Safety precautions when removing the…↡
Petrol models
The fuel system consists of: installed in the rear of the vehicle (under the rear seat cushion) fuel tank with activated carbon adsorber, fuel lines, electric fuel pump, and electronic sequential injection system controlled by the control unit.
The fuel reserve is shown to the driver on the instrument panel. In a gasoline engine, gasoline vapors are collected in the adsorber and fed into the combustion chambers of the engine.
Driving style has a significant impact on fuel consumption. Below are some tips on how to use the gas pedal wisely.
- Once the engine starts, move off immediately, even if it is in freezing temperatures;
- If the vehicle is stopped for more than 40 seconds, turn off the engine;
- Always drive in the highest possible gear;
- When driving long distances, maintain a steady speed whenever possible. Avoid driving at high speeds. Drive carefully. Do not brake unnecessarily;
- Do not carry unnecessary loads on the vehicle. If the luggage rack is not in use, remove it from the roof;
- Check the air pressure in your tires. Do not allow the pressure to drop too much.
Diesel models
The fuel system consists of: installed in the rear of the vehicle (under the rear seat cushion) fuel tank, fuel filter, injectors, fuel lines and hoses, fuel level sensor located inside the tank and the engine control unit.
Fuel is supplied by a special pump through a filter. The filter collects dirt and water contained in the fuel.
The engine is controlled by an electronic system similar to that of gasoline engines. The system controls the engine by analyzing information from a large number of sensors.
Diesel models do not have an accelerator cable. Instead, a pedal position sensor is installed on the pedal.
(Publication taken from an online resource: mercedesman.ru)
There is no fuel shut-off valve when the ignition is turned off. In order to shut off the engine when the ignition is turned off, the engine control unit sends a signal to the fuel injection pump control unit, which, in turn, stops the fuel supply to the injectors.
The fuel system is designed to prevent air "sucking" in when there is no fuel in the tank. The control unit constantly checks the fuel level in the tank, processing information coming from the fuel reserve sensor located in the tank. When the fuel reserve drops to a certain level, the control unit activates the control lamp on the instrument cluster, after which it forcibly causes fuel supply misfires, thereby limiting the maximum speed. This continues until the fuel level in the tank exceeds the permissible mark.
The fuel system of diesel engines is very reliable. If clean fuel is used and regular maintenance is performed, it should function properly until the end of the vehicle's service life. After very high mileage, the internal components of the injectors may wear out and need to be repaired. Since the pump-injectors have a complex design, it is recommended that repairs be carried out in a specialized workshop.
Safety precautions and rules for maintaining cleanliness when working with the fuel system
When working with the fuel system, the following safety and cleanliness measures must be observed:
- Do not approach the work site with open fire, do not smoke and do not turn on any heating devices! Keep a fire extinguisher at hand;
- Ensure proper ventilation of the workplace - fuel vapors are toxic;
- The fuel system is under pressure. When opening the system, fuel may escape under pressure - use protective glasses. Collect spilled fuel with a rag;
- When working with components of the diesel engine fuel system, take special precautions. This applies especially to injectors. Keep in mind that the fuel pressure when leaving the injectors is about 1100 atm - do not allow any part of your body to come under the fuel stream;
- Hose connections are secured using tape or clamp clamps. Clamp clamps must be replaced with tape clamps or clamps of the latest design. Special devices are available for installing tape clamps (for example, HAZET 796-5);
- Thoroughly clean connections and adjacent areas before opening;
- Place the removed components on a clean surface and cover with plastic, paper or a LINT-FREE rag;
- Carefully close open ends of nipple connectors or seal them with suitable plugs;
- Install only clean parts - remove replacement components from packaging only immediately before installation. Do not use parts that have been stored unpackaged;
- Avoid using compressed air when the fuel system is open, and try not to move the vehicle if possible;
- Do not use sealants containing silicone - silicone particles that get into the engine do not burn and may cause the oxygen sensors to fail.
Safety precautions when removing the fuel tank
- Before removing the tank, drain the fuel from it or pump out the fuel using a pump specially designed for this purpose;
- The fuel tank is removed from the underside of the vehicle. Before disconnecting the tank mounting clamps, place a jack and shims underneath the tank;
- An empty tank is explosive and cannot be disposed of in this form. Before disposal, the tank must be cut into pieces. Make sure that no sparks are generated. To do this, hand over the fuel tank to a specialized company;
- After installing the tank in place, start the engine and check the tightness of all connections.