| Fuel pressure regulating valve -N276--5- is located on rail element (high-pressure accumulator). |
Note | The fuel pressure regulating valve -N276- cannot be re-used. |
| »Carry out the following work sequence« |
| The high-pressure accumulator must be removed later. |
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| Before removing the high-pressure accumulator, first clean it (e.g., with commercial cleaning solution). |
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| The area on the thread around the fuel pressure regulating valve -N276- must also be thoroughly cleaned. |
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| Under no circumstances may dirt enter the borehole of the fuel distributor. |
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| It must be ensured that no cleaning agent gets into the connector housing of the fuel pressure control valve -N276-. |
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| Collect escaping fuel with a cleaning cloth. |
Note | Seal off open connections immediately using a suitable plug to prevent dirt from entering. |
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| Remove rail element (high-pressure accumulator) → Chapter. |
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| Dry fuel pressure regulating valve -N276-. |
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| For loosening, counterhold the union nut on the hexagon flats on housing. Then unscrew and remove by hand. |
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| Extract dirt from threads and sealing surfaces. Do not use metal tools, etc. |
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| The fuel pressure regulating valve -N276- has a deformable sealing lip and no separate seal; it can therefore be used only once. |
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| Make sure that sealing surfaces (deformable sealing lip) and threads on new fuel pressure regulating valve -N276- are undamaged. |
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| Check sealing surface hole. |
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| The beginning of the thread and the deformable sealing lip of the fuel pressure regulating valve -N276- must be lubricated with Molykote grease. |
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| Align fuel pressure regulating valve -N276- so that connecting wire is free of tension after electrical connector is attached. |
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| Hold with socket spanner and tighten the screw connection. |
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| Tightening torque: Rail (High-pressure accumulator): Assembly overview → Chapter |
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| Install rail element (high-pressure accumulator) → Chapter. |
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| After installing, leave engine running at moderate speed for a few minutes and then switch off again. |
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| Check fuel system for leaks . |
Note | If the fuel pressure regulating valve -N276- or the high-pressure pump has been exchanged, it is essential that the learnt values for the regulating valve be reset using the vehicle diagnosis tester. Guided Functions; Reset the learn values of the control valve for fuel pressure. |
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| Then road-test the vehicle. Accelerate with full throttle at least once, then check the high-pressure section again for leaks. |
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| Read fault memory again. |
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