Note.
- If the pressure in the high pressure fuel circuit is too high, open the control valve and some of the fuel from the fuel rail returns through the fuel return line back to the fuel tank.
- If the pressure in the high pressure fuel circuit is too low, the control valve closes, thus separating the high pressure side from the low pressure side.
Note. Fuel pressure regulating valve -N276- must not be reused.
Note.
- Necessary special devices, control and measuring devices, as well as auxiliary means:
- Cleaning and degreasing agent, e.g. -D 009401 04-.
- Protective goggles and gloves.
- Socket wrench No. 36.
Removing
Note. When working on the power supply system, safety precautions must be observed.
1. Remove the fuel rail.
Attention. Wear protective gloves and goggles when working with the degreaser!
2. Before removal, clean the thread area around the fuel pressure control valve with a degreasing agent - no contamination should be allowed to enter the fuel rail opening.
Note. Do not let the degreaser get into the connector of the wiring harness; clean carefully.
3. Drain fuel pressure regulating valve -N276-.
4. Loosen fuel pressure regulating valve -N276-. Then twist by hand.
5. Remove dirt from the fuel rail opening (thread and sealing surface). Do not use mechanical tools for this.
Note. The fuel rail opening must be closed immediately with a suitable plug to prevent the entry of contaminants.
Installation
Note.
- The fuel pressure regulating valve -N276- does not have a sealing ring, but a special sealing lip.
- Take care not to damage the sealing surfaces (sealing with a special sealing lip) and the thread of the new fuel pressure regulating valve -N276-.
- Also check the sealing surface of the fuel rail opening.
- Lubricate the threaded end and the special lip of the fuel pressure regulating valve -N276- with Molykote grease.
1. For tightening, use a box wrench No. 36.
2. Install the fuel rail.
3. Check the tightness of the power system.
Note. If the fuel pressure regulating valve -N276- is replaced, the stored values of the regulating valve must be reset.