Cummins/Onan — Injector Supply Lines (High Pressure) - Vent
Maintenance · fuel system - high pressure lines
From a Cummins/Onan owner's manual covering: 4B3.9, 4BT 3.9, 4BTA 3.9, 6B5.9, 6BT 5.9, 6BTA5.9, B3.9, B5.9, C8.3. Check it applies to your exact model before use.
Applies to: Cummins/Onan 4B3.9, Cummins/Onan 6BTA5.9, Cummins/Onan B5.9 engine
Before you start
- While testing the injectors, keep hands and body parts away from the injector nozzle.
- Do not bleed the fuel system on a hot engine.
Procedure
- Loosen one or more fittings at the injectors.
- Crank the engine to allow entrapped air to bleed from the lines.
- Start the engine and vent one line at a time until the engine runs smoothly.
- Tighten the line fittings to 30 N*m [22 ft-lb].
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Torque Value: 30 N*m [22 ft-lb]
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.