Diesel MFI Pump: Testing and Inspection

With the Bosch VP44 injection pump, there are no mechanical adjustments needed for fuel injection timing. All timing and fuel adjustments are made by the Engine Control Module (ECM). However, if a Diagnostic Trouble Code (DTC) has been stored indicating an "engine sync error" or a "static timing error", perform the following.

NOTE: If this DTC appears after installation of a new or rebuilt injection pump, the pump key-way has probably been installed backwards. Refer to Fuel Injection Pump Removal/Installation for keyway information.

Fig. 30 Crankcase Vent Hose:

1. Remove hose clamp and crankcase vent hose at crankcase breather (Fig. 30). Remove crankcase breather from gear cover. Breather threads into cover.

Fig. 31 Injection Pump Gear Nut/Washer:

2. Remove injection pump nut and washer (Fig. 31). Locate keyway behind washer.
3. Be sure keyway aligning fuel injection pump shaft to injection pump gear is in proper position and pump gear has not slipped on pump shaft.
The following steps will require removing timing gear cover to gain access to timing gears.
4. Use a T-type puller to separate injection pump gear from pump shaft.

Fig. 32 Pump Keyway, Keyway Arrow And Keyway Number:

5. Be sure keyway has been installed with arrow pointed to rear of pump (Fig. 32).

Fig. 33 Pump Data Plate Location:

6. Pump timing has been calibrated to pump keyway. Be sure 3-digit number on pump keyway (Fig. 32) matches 3-digit number on fuel injection pump data plate. Plate is located on side of injection pump (Fig. 33). Twenty-one different calibrated keyways/pumps are available.

Fig. 34 Checking Fuel Injection Pump Gear Timing:

7. Verify timing marks on crank, cam and pump are aligned (Fig. 34).
8. Perform necessary gear alignment/repairs as needed.
9. Install crankcase breather to gear cover. Install hose clamp and crankcase vent hose to breather (Fig. 30).
10. After repairs are completed, erase DTC using DRB Scan Tool.