High Pressure Method
ADJUSTING INJECTION TIMING (BEGIN OF DELIVERY) (HIGH PRESSURE METHOD) - FOLLOWING CHECKUPSpecial tool
Note: Prior to adjustment, check injection timing.
A. Preparing for adjustment
1. Set crankshaft in direction of rotation to 240 + 10 before TDC in compression stroke of first cylinder.
2. Loosen fastening nuts on injection pump flange and nut or screw on supporting bracket.
For loosening and tightening of fastening nuts or screws on supporting bracket, use self-bent box end wrench 13 mm.
B. Adjustment (high pressure method)
1. Unscrew all injection lines.
2. Screw pressure limiting valves (arrow) on pipe connections of injection pump.
The pressure limiting valves are required to protect the injection pump, e.g. when cranking with starter.
3. Switch on pump unit.
4. Swivel injection pump while watching fuel jet.
Begin of delivery is attained, when the fuel jet changes into a formation of droplets (arrow).
Nominal value: 24° + 1° before TDC.
Swivel direction of injection pump
Toward engine advances begin of delivery
Away from engine retards begin of delivery
Note: If possibilities for adjustment are insufficient, the injection pump must be changed over.
5. Check begin of delivery once again.
6. Shut off pump unit.
7. Assemble injection system.
8. Vent injection system. Service and Repair Run engine and check all connections for leaks.
C. Adjustment (low pressure method)
1. Swivel injection pump until fuel changes to droplets at overflow pipe. Formation of droplets:
One droplet per second.
Attention! While measuring, push regulating lever of injection pump to full load and pull vacuum hose from vacuum control unit.
Note: On pipe connections with relief orifice (2), no full fuel jet will come out of overflow pipe. However, measuring accuracy will not be impaired.
Swivelling direction
toward engine = advances begin of delivery,
away from engine = retards begin of delivery.
Note: Injection pump will have to be relocated if adjustment is inadequate. Installation of Injection Pump (With Locking Screw)
2. Attach injection pump and recheck begin of delivery.
Install damper, adjust. Removal and Installation of Injection Pump
3. Attach injection pump.
4. Unscrew overflow pipe and pipe connection.
5. Fit pipe connection.
Remove delivery valve holder (6), checking whether delivery valve (4) moves freely in holder (6).
Insert delivery valve holder (6) with annular groove pointing downward.
Attention! Starting with Bosch production date "249" (September 1982) the annular groove should point upwards.
The copper sealing ring is located beneath the delivery valve holder and need not be exchanged.
Smear thread of pipe connection (1) with oil, insert connection and torque to 40-50 Nm in one step.
6. Fit injection lines and vent injection system. Service and Repair
7. Check throttle linkage and adjust, if required.
8. Run engine and check all connections for leakage. Any pipe connection that is leaking has to be exchanged. In this case exchange copper sealing ring beneath delivery valve holder. Replacement of Pipe Connection, Delivery Valve or Sealing Ring