Injection Pump - High-Pressure Timing
85mercedes02 REF. NO. 07.1/13INTRODUCTION
The high-pressure method of injection timing is recommended over drip timing since the high-pressure method is more accurate than drip timing, and the number-1 cylinder delivery valve does not need to be disassembled. Use the following special tools and procedure for high-pressure injection timing:
SPECIAL TOOLS NEEDED
High-Pressure Pump Kit 422 589 00 71 00
Adapters and Plug Kit (Six Needed) 403 589 00 91 00
High-Pressure Valves (Five Needed) 617 589 00 91 31
Adjustment Screw 98 352 589 00 21 00
Injection Line Socket (Crowfoot) 000 589 68 03 00
Fig. 1 - High-Pressure Pump Kit:
1. Electric Motor (12 Vdc, 15 A)
2. Gear Pump
3. Pressure Limiter Valve
4. Fuel Reservoir
5. Fuel Return Line
6. Sight-Glass and Test Line
7. Power Leads 8.. Fuel Delivery Line
9. Base Plate
0. Relay Box and Switch
Fig. 2 - Fuel Line Connections:
Fig. 3 - High-Pressure Pump Connections:
PROCEDURE
NOTE: Before beginning injection pump timing, clean the engine to prevent road dirt, grease, or other foreign matter from entering the engine.
NOTE: For steps 1 through 3, see Figs. 2 and 3.
1. Remove the two capscrews securing the fuel filter bracket to the cylinder head. With the fuel lines still connected, move the fuel filters and bracket out of the way.
2. Disconnect the fuel delivery line at the injection pump (Fig. 2, Ref. 1), and in its place connect the high-pressure pump delivery line from kit 422 589 00 71 00 (Fig. 3, Ref. 1). Tighten the hollow capscrew 35 N-m (26 ft.lbs).
WARNING: Do not substitute unapproved parts for kit components or fuel lines. Extremely high pressures are developed which could cause substitute parts to fail allowing fuel to escape under high pressure, possibly causing serious injury. Use only approved replacement parts.
3. Disconnect the fuel return line at the injection pump (Fig. 2, Ref. 2). Close the return line port with the plug from adapter set 403 589 00 91 00 (Fig. 3, Ref. 2). Tighten the plug 35 N-m (26 ft.lbs).
NOTE: The fuel return line hollow capscrew contains the pressure relief valve. It is not necessary to disassemble the pressure relief valve.
Fig. 4 - Disconnecting Number-1 Injection Line:
Fig. 5 - Sight-Glass and One High-Pressure Valve Installed:
4. Disconnect the injection line from the number-1 delivery tower on the injection pump (Fig. 4). Install an adapter from the adapter kit. Tighten the adapter 25 N-m (18 ft.lbs). Connect the test line with the sight-glass to the adapter (Fig. 5). While holding the adapter with a wrench, tighten the test-line nut 25 N-m (18 ft.lbs). Insert the return end of the sight-glass test line into the high-pressure pump reservoir. See Fig. 3, Ref. 6.
5. Disconnect the remaining injection lines at the injection pump. Install an adapter on each delivery tower, and tighten the adapters 25 N-m (18 ft.lbs). Install the high-pressure valves (617 589 00 91 31); while holding the adapters with a wrench, tighten them 25 N-m (18 ft.lbs).
WARNING: Disconnect the injection lines and install high-pressure valves on the remaining delivery towers. This is necessary to prevent the accidental starting of the engine and possible personal injury.
CAUTION: Do not kink, twist, or nick the injection lines. Restrictions or weak spots could result, causing a line to fail.
6. To provide access to the flywheel ring gear, remove the clutch-housing dust shield. Use the flywheel ring gear to turn the engine.
CAUTION: Never use the fan blades to turn the engine. A bent fan blade can cause water pump bearing failure, radiator core damage, or cracking of the fan blade. Use the flywheel ring gear to turn the engine when lining up timing marks.
7. Turn the engine clockwise (as viewed from the front) until the vibration damper is approximately 180 degrees (1/2-turn) before the "OT" mark.
8. With the switch in the "O" (off) position, connect the high-pressure pump to a 12-volt battery.
WARNING: Do not adjust or loosen any fuel system connections while the high-pressure pump is turned on. Fuel could escape under high pressure and cause serious injury. Turn the pump off before working on the fuel system connections.
NOTE: The high-pressure pump switch is labeled, "I" and "O." When the switch is in the "I" position, the pump is turned ON. When the switch is in the "O" position, the pump is turned OFF.
9. Use a spring or wire to tie the injection pump throttle lever in the full-load position; then turn the highpressure pump on.
Fig. 6 - Fuel Flow Through the Sight-Glass:
10. Turn the engine slowly clockwise and observe the sight-glass until the fuel delivery changes from a constricted flow to a series of drops. Start of delivery (Fuel Begin) is precisely at the transition from restricted flow to a series of drops. See Fig. 6.
NOTE: If the fuel stops flowing, turn the engine counterclockwise 90 degrees (1/4-turn) to remove gear backlash before again turning the engine slowly clockwise.
Fig. 7 - "FB" Mark and Pointer Aligned:
11. Check to see if the "FB" (Fuel Begin) mark on the vibration damper is aligned with the "FB" pointer on the timing cover (Fig. 7). If the marks are not aligned, the fuel delivery timing must be adjusted as follows:
.1 Turn the high-pressure pump off.
.2 Turn the engine in a clockwise direction until the "FB" mark on the vibration damper lines up with the "FB" pointer on the timing cover.
NOTE: Turn the engine clockwise to line up the marks. Turning the engine counterclockwise would produce incorrect timing due to gear backlash.
Fig. 8 - Injection Pump Capscrews:
.3 Loosen the four injection pump flange capscrews. See Fig. 8, Ref. 1.
.4 Turn the high-pressure pump on.
.5 Move the injection pump toward the engine until a steady stream of fuel flows in the sight-glass.
.6 Install adjustment screw 98 352 589 00 21 00.
.7 Turn the knob on the adjustment screw clockwise to move the top of the injection pump slowly
away from the engine until the fuel flow in the sight-glass is reduced to a series of drops. Lock the injection pump in position by tightening one flange capscrew.
8. Check the timing by turning the engine 90 degrees (1/4-turn) counterclockwise. A steady fuel stream should flow in the sight-glass. Turn the engine clockwise until the fuel flow is reduced to a series of drops. The "FB" mark must now line up with the "FB" pointer.
NOTE: If the fuel stops flowing, turn the engine counterclockwise 90 degrees (1/4-turn) to remove gear backlash before again turning the engine slowly clockwise.
9. Tighten all four injection pump flange capscrews 50 N-m (37 ft.lbs.).
10. Remove the adjustment screw.
12. Turn the high-pressure pump off.
13. Remove the spring or wire from the injection pump throttle lever.
14. Disconnect the high-pressure pump fuel delivery line and connect the vehicle's fuel delivery line. Check the sealing washers and replace them if they are worn or damaged. Tighten the hollow capscrew 35 N-m (26 ft.lbs.).
15. Remove the test line, sight-glass, and adapter from the number-1 delivery tower. Connect the injection line. Use socket 000 589 68 03 00 to tighten the nut 25 N-m (18 ft.lbs.).
16. Remove the high-pressure valves and adapters from the remaining delivery towers. Connect the injection lines. Use socket 000 589 68 03 00 to tighten the nuts 25 N-m (18 ft.lbs.).
17. Remove the plug from the return line port and connect the fuel return line. Check the sealing washers for wear or damage, and replace them if necessary. Tighten the hollow capscrew (containing the pressure relief valve) 35 N-m (26 ft.lbs.).
18. Install the fuel filter bracket. Tighten the bracket capscrews 47 N-m (35 ft.lbs.).
19. Bleed the fuel system. Refer to the L Model Workshop Manual, Group 07.1, Job 190, for instructions.
20. Install the clutch-housing dust shield.