Table of contents: Valve injectors - removal and… ↓ Fuel Shut-Off Valve - Check ↓
Below are the types of repair work related to the fuel system of a diesel engine, available to a car enthusiast. This list may be wider, for example, to eliminate a leak on the fuel injection pump is within the power of a car enthusiast. However, such work will be performed by an AUDI workshop with higher quality.
Valve injectors - removal and inspection
1. Purchase new heat shields for the injectors.
2. Disconnect the high-pressure fuel lines. Do not change the bend shape of the fuel lines (see illustration).
3. Remove the fuel return hoses.
4. Unscrew the injectors using a 27 mm socket or socket wrench.
5. Use a ballpoint pen or a wire hook to remove any remaining heat shields from the nozzle opening.
6. Install new heat shields (see illustration).
7. Screw in the injectors and tighten them to a torque of 70 Nm.
8. Reinstall the high-pressure fuel lines and tighten them to 25 Nm. A higher tightening torque will cause the flow orifice to become narrower.
Valve injectors installed on cars manufactured before 6/92 are disassemblable. Disassembly and assembly of injectors should be entrusted to a workshop. Two-spring injectors installed from 7/92 are non-disassemblable. In case of a malfunction, such an injector can only be replaced with a new one (see illustration 4.0).
4.0 Parts of the valve injector for cars produced before 6/92.
1 - lower part of the nozzle (turnkey for 27)
2 - nozzle body
3 - injector needle
4 - fuel return valve
5 - pressure bolt
6 - spring
7 - adjusting washer
8 - upper part of the nozzle (turnkey for 27)
Fuel Shut-Off Valve - Check
In order to stop the engine, the fuel shut-off valve closes the fuel supply to the injectors. If the fuel shut-off valve fails, the engine cannot be started. If the engine does not start, despite the fact that the fuel tank is full and the preheating system is normal, then the valve may be faulty.
9. First of all, make sure that the fuel cut-off valve power wire is normal.
10. Ask an assistant to turn the key in the ignition switch, and listen to see if the fuel shut-off valve is triggered. When triggered, the valve makes a fairly loud clicking sound. If there is no such sound, then the cause of the malfunction is the lack of power to the valve or in the valve itself.
11. Check the voltage supply to the valve. To do this, turn on the ignition and connect a tester with a diode lamp to the valve contact. If the lamp lights up, the valve itself is faulty. Otherwise, the power supply wire from the ignition switch is faulty. Despite the valve malfunction or interruptions in its power supply, the trip can be continued.
12. Disconnect the wire from the fuel shut-off valve.
13. Unscrew the valve from the high-pressure fuel pump.
14. Remove the valve piston (see illustration).
15. Screw the valve body back into place to ensure a tight seal for the system.
16. Start the engine. It will start as usual, but you will need to turn off the engine with the gear engaged.
[The text is based on materials from the website: AudiManual.ru]