Fuel Pressure Regulator Valve -N276-: Installing
Install in reverse order of removal. Note the following:
The Fuel Pressure Regulator Valve -N276- has a biting edge instead of a sealing ring and cannot be reused.
Check the new Fuel Pressure Regulator Valve -N276- sealing surface and threads for damage.
Check the sealing surface on the hole inside the fuel rail.
Coat the biting edge of the threaded insert and the O-ring for the Fuel Pressure Regulator Valve -N276- with diesel fuel.
-- Align the Fuel Pressure Regulator Valve -N276- such that connecting the harness connector -arrow- does not cause the electrical wiring to be placed under tension.
-- Counterhold the housing hex bolt to tighten regulator valve tightening union nut in 4 stages as follows:
- Tightening specification, refer to Figure
-- Replace gaskets on fuel return line banjo bolts and tighten to 25 Nm.
Fuel System, Bleeding and Performing a Leak Test
-- After installing, let the engine run at a moderate speed for a few minutes and then stop it.
The high pressure connections must "not" be opened; the fuel system bleeds itself.
-- Check Diagnostic Trouble Code (DTC) memory and erase, if necessary.
-- Turn off ignition.
-- Carefully check the entire fuel system for leaks.
If there are leaks even though the correct tightening specification was used, replace the affected component.
Perform an adaptation after replacing the high pressure pump and / or the Fuel Pressure Regulator Valve -N276-. Use a Vehicle Diagnostic Tester to do this.
-- Perform a road test where the accelerator pedal is pressed all the way down at least one time. Then check the high pressure area again for leaks.
If there is still air in the fuel system, the engine may switch to emergency mode during the road test. Turn off the engine and erase the Diagnostic Trouble Code (DTC) memory. Then continue the road test.
-- After the road test, check the DTC memory again.