Replacing the injection pump normally involves removal of an engine mount, for transverse or small-engine diesels, removal of all accessory components, the timing cover, timing components, high and low pressure fuel lines, and finally, the pump and associated electrical connectors may be removed. Reassembly is the reverse of removal, and if the pump failed, the system will be thoroughly inspected before allowing the vehicle to restart.
Full step-by-step procedures for the two common types of diesel injection pumps can be found below:
Gear Driven Injection Pump
- Disconnect the negative battery terminal
- Remove any components that obstruct access to the injection pump
- Disconnect all fuel lines and electrical connectors to the injector pump
- Remove the injector drive gear cover, if equipped
- Lock the injector drive gear in place with the locking pin
- Remove the fasteners that secure the injector pump
- Remove the old injector pump and clean the mounting area
- Install the new injector pump and "time it" with the drive gear
- Secure the new injector pump with its fasteners
- Reconnect all electrical connectors and fuel lines
- Install any other removed components
- Reconnect the negative battery terminal and clear any codes
- Start the engine and verify the injector timing with the proper tool
- Perform a comprehensive test drive to verify the repair
Timing Belt Driven Injection Pump
- Disconnect the negative battery terminal
- Remove any drive belts that block access to the injection pump
- Disconnect any fuel lines and electrical connectors
- Remove the timing belt cover(s) and, by hand, rotate the engine to the timing marks
- Loosen the timing belt and pull it back from the injection pump
- Remove the injection pump fasteners and the injection pump
- Clean the mounting area and install the new injection pump
- Secure the injection pump fasteners and re-attach the timing belt
- Verify that the alignment of the timing marks are still correct
- Install the timing cover, drive belts, fuel lines, and electrical connectors
- Reconnect the negative battery terminal and clear any codes
- Perform a comprehensive test drive to verify the repair
