- Remove the timing belt cover.
- Unscrew the plug of the hole (1) for checking the top dead center in Figure 289.
- Disconnect the injection pipes from the rear of the pump. A plug is visible between the injection tube connection points (position 2 in figure 296), closing the hole for adjusting injection timing. Unscrew this plug.
Figure 295 Disconnect both hoses (1) from the top of the high pressure fuel pump.
Figure 296. After removing the injection tubes (1), unscrew the plug (2) from the rear side of the pump.
- Screw in the dial indicator from the tool kit with an extension and stand in place of the plug, and install the measuring probe with a pre-tension of 1.0 mm. Figure 297 shows how to install the measuring instruments.
Figure 297. Adjusting the Bosch high-pressure fuel pump. The mounting bolts are indicated by arrows.
- Determine the top dead center position of the fourth cylinder by rotating the crankshaft in both directions and finding the maximum reading on the dial indicator scale in Figure 297. The initial tension of the measuring gauge should be 1.0 mm. When checking, observe the scale as shown in Figure 298. Dimension "X" is the value to be set.
Figure 298. To obtain the dimension "X", you can read the arrow on the scale in the manner shown.
- Reset the dial indicator scale to zero by turning the outer ring of the device.
- Turn the engine in the operating direction to a position where the locking rod can be inserted into the cylinder block, as shown in Figure 293.
- Take a reading from the dial indicator scale. It may vary for different engine types and is taken from the engine specification tables ("static injection timing"). Two possible values for different engine types are 0.83 mm or 0.90 mm, with a tolerance of plus or minus 0.03 mm. If the scale reading deviates from the specified value, adjustment is required.
- Remove the front pump bolts (arrows in figure 297) and the support bolts from the rear side and tilt the pump away from the motor and outward.
- Slowly turn the pump towards the engine until the dial gauge reading is equal to the specified value. Tighten the front bolts to a torque of 20 Nm and the rear bolts to a torque of 22 Nm. While tightening the bolts, observe the dial indicator readings in Figure 298, as they should not change (a change in readings means that the adjusted position of the pump is violated).
- Check the pump adjustment again as described above and remove all instruments and devices. Screw the plugs into the cylinder head (30 Nm) and the back of the pump (20 Nm).
- Connect the injection pipes. Tighten the union nuts to a torque of 20 Nm.
- Screw in the glow plugs with a tightening torque of 22 Nm. Connect the wires.
- Install the timing belt cover.
- All other work is carried out in reverse order. Start the engine. Check engine operation and possibly make additional adjustments.
- It is possible to check the adjustments described in section 19.6 and, if necessary, adjust them according to the relevant instructions. Be sure to read the section on the Bosch high-pressure fuel pump.