High Pressure Method

Checking injection pump for begin of delivery (according to high pressure - overflow method)

Test Values:

Attention! On MW- and M/RSF-injection pumps with mechanical governor push regulating lever of injection pump to full load while measuring and remove vacuum hose from vacuum control unit

Tightening Torques:

Special Tools:

Checking

1 Clean injection lines in range of coupling nuts on injection pump as well as on fuel filter.

2 Move control rod of injection pump to full load.

For M-injection pump with pneumatic governor:



Move preglow starter switch on instrument panel to driving position "2". In this position, the play between adjusting lever and long-slot eye should be at least 2 mm (distance "a").
Adjust cable control, if required.

For MW- and M/RSF-injection pump with mechanical governor






Pull vacuum hose from vacuum control unit. Lock regulating lever of injection pump to full load.




3 Unscrew injection line for cylinder 1.

On injection pump, screw-on test line with sight glass and install return line to fuel tank of pump unit.










4 Close fuel return line from injection pump to fuel filter, depending on filter version.







On 3rd version of fuel filter, place 0-ring into ring fitting (2) of return line and energetically push-in quick-action lock.




5 Connect feed line (3) to injection pump with connecting line (4) of pump unit by means of a double hollow screw. Close connecting holes on fuel filter with closing plugs (arrows).




On fuel filters of 1st version, the fuel feed to injection pump is located on lower half of filter. On this version, the pump unit is connected directly to injection pump. Close screwed-off line.

6 Clamp connecting cable of pump unit to vehicle battery (red terminal positive, black terminal negative).

7 Rotate crankshaft in direction of rotation of engine up to approx. 350 before TDC in compression stroke of first cylinder. Engage pump unit.

Attention! Engage pump unit only for measuring. If an injection nozzle is leaking, fuel may enter combustion chamber.

8 Slowly rotate crankshaft in direction of rotation of engine, while watching fuel jet in sight glass.







If fuel jet turns into a chain of drops, begin of delivery has been attained.

In this position, read begin of delivery on graduated scale on balancing disc.

Nominal value: 24° or 26° before TDC.

9 Disconnect pump unit. Assemble injection system.

10 Vent injection system. Service and Repair Run engine and check all connections for leaks.

Connection Diagram: