High pressure fuel pump (HPFP) (Mercedes-Benz Vario 814)

Removal

1. Disconnect the negative cable from the battery.

2. Remove the cylinder head.

3. Set the piston of the first cylinder to the position 12° before TDC. Both cams of the first cylinder should be directed upwards.

4. Disconnect fuel pipes 14 and 15 from high-pressure fuel pump 1 (figure 2.70).



5. Disconnect the electrical wiring from the fuel injection pump. To do this:

• Remove the cable mounting bolts (arrow) from the fuel pump shut-off valve (figure 2.71);

• Disconnect the wiring connector from the two temperature sensors on the instrument cluster 1 and MSA15 2 on the cylinder head (figure 2.72a,b);

• Disconnect the wiring connectors from the fuel injection timing control regulator and the injector needle travel sensor (arrows) (figure 2.73);

• Disconnect the wiring connector from the fuel flow meter behind the left headlight (figure 2.74).

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6. Disconnect the fuel pipes 4

7. Unscrew bolt 10 and remove gasket 11 from support bracket 9 and the rear part of the fuel injection pump retainer.

6. Unscrew bolts: 13 with gaskets 12 from the cylinder block and remove support bracket 9.

9. Remove the high-pressure fuel pump 1 from the intermediate flange.

10. Remove the disc with the toothed ring 16 (only if the fuel injection pump is removed). To do this:

• Attach the key to the disk and unscrew the mounting nut (figure 2.75);

• Using a puller, remove the disc (figure 2.76).

Installation

11. Check the radial seal of the intermediate flange. Replace it if necessary. To do this:

• Using a screwdriver, remove the intermediate flange seal outward (figure 2.77);

• Using punch 1, install new seal 11 into intermediate flange (figure 2.78).

12. Install the toothed ring disc (figure 2.79). Before installing the disc, remove grease from the drive shaft. Attach the woodruff disc to the pump and tighten the nut.



13. Install the fuel injection pump.

14. Further installation is carried out in the reverse order of removal.

15. Start the engine and check the start of fuel injection using a tester (Fig. 2.80). If the engine does not start, unscrew the fuel pipe for the first cylinder and bleed it.



16. To check the start of injection using a tester, do the following:;

• Start the engine and warm it up to operating temperature;
• Turn off the engine;
• Loosen the bolts of the intermediate flange 1 and the support bracket 2;
• Connect the tester to the diagnostic connector to check the start of fuel injection;
• Start the engine;
• Set the tester to the "Fuel injection quantity control" position;
• Determine the start of fuel injection with a tester and adjust it with screw 3 on the intermediate flange. To the right - late injection, to the left - early injection;
• Tighten bolt 2 on the support bracket and bolts 1 on the intermediate flange;
• Read the fault codes stored in the memory and clear them if necessary.
• Start the engine, then turn it off and check for leaks.