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Fuel injection
VW T4 petrol engines are equipped with fuel injection Digifant VW. The advantages of the fuel injection as compared with the carburetor are:
- Precise dosage of fuel in all operating conditions of the engine with lower fuel consumption and good driving performance;
- Reduction of emissions as a result of precisely metered fuel;
- The ability to cleanse the exhaust gas lambda way catalyst;
- Self-test control unit injection, so that - fast finding fault;
- Injection system is equipped with memory, which records fault.
If, during operation of the injection system and engine faults occur, they are stored in memory. The recorded faults may be by polling memory block VW printed. If the injection system is faulty or the engine running, at the CTO-VW can print a list of faults for further elimination.
A warning  If disconnected battery, the fault memory is erased. If the fault occurs while driving again, she writes.
The injection system consists of a little wearing parts and almost natrebuet service, only the air filter element needs to be replaced every 30,000 km.
Major repair and adjustment work may only be performed with the help of expensive control units VW, so that such work can only be carried out respectively equipped with SRT.
A warning When working in the injection system must be subject to the same rules of cleanliness as when handling ignition system.
Works in the injection system hampered the short bonnet, restrict access to the engine compartment. On this basis the radiator grille and the fan with just folded forward. Folding radiator is required when carrying out almost all work in the injection system and described in Section 2.2. INJECTION DIGIFANT
The system developed by VW AG Digifant In this system, the electronic control unit integrated control system of ignition and injection system.
Fuel is drawn from the fuel tank and the electric fuel pump through the fuel filter on the bottom is fed to the fuel distributor, then to the injection valve. The pressure regulator on the wand looks the fuel supply system of constant pressure of about 2.5 bar. Vibration damper pressure regulator reduces the pressure fluctuations in the conduit return flow of fuel.
Air is sucked through the engine through the air cleaner and the throttle pipe and the intake manifold enters the engine. Throttle position is measured and the potentiometer for the control unit together with the engine speed at the moment and a measure of the vacuum inlet tube for controlling the air flow.
The control unit, depending on the amount of supplied air, regulates the injection time and injection quantity. The longer the injection valves are opened, the greater the amount of fuel injected. Additional probes and sensors are monitored in special operating conditions for correctly measured amount of fuel.
The control valve regulates the stabilization of idling the idle speed, especially during the warm-up phase, and if the motor is loaded with appliances included.
Throttle potentiometer is located directly on the platen throttle. It tells the control unit the position of the throttle, especially idling and full power, so the switch is managed traction. If the machine is moving without using the drive force of inertia, the control unit shuts off the fuel to the engine. In this case the throttle is at idle position and the engine speed are slightly above 1500 rev / min.
The pressure sensor is located in the control unit and is connected by a hose to the inlet pipe.
Hall sensor in the ignition distributor informs the control unit about the number of revolutions at a given time.
The valve of cold start during cold start further injects fuel into the intake manifold. Faulty valve cold start creates difficulties when starting the engine (hot and cold), poor acceleration and increases fuel consumption.
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