Replacing injectors on a 5.9 Cummins engine

Replacing injectors on a 5.9 Cummins engine requires precision and attention to detail. Here’s a step-by-step guide:

1. Preparation:
Park the vehicle on a flat, level surface.
Disconnect the negative battery terminal.

2. Injector Removal:
Remove the valve cover, dipstick tube, air inlet, and intake heater to access the fuel injector. Loosen and remove the high-pressure fuel line, electrical connectors, exhaust rocker, and crossover tube from the injector.
Pull out the old injector, ensuring the copper washer and o-ring come out with it.

3. New Injector Installation:
Lubricate the o-ring of the new injector and insert it into the hole until it clicks.
Install the new crossover tube and torque the hold-down nut.
Reconnect the electrical connectors and high-pressure fuel line.

4. Torque Values (Always consult the service manual):
Injector bolts: Initial tightening to 44 in-lbs, then relieve bolt torque.
High-pressure connector nut: Preliminary torque of 11 ft-lbs, then final torque to 37 ft-lbs.

Remember to handle injectors delicately—they’re sensitive components!