Fuel Injector Lines Fit 1989 91 Cummins Engine 12V 5.9L 3960783 3960784

Product Overview

These fuel injector lines are engineered to deliver high-pressure fuel to the injectors on 1989–1991 Cummins 12V 5.9L diesel engines. They precisely replace OEM parts 3960783 and 3960784, ensuring proper fuel timing and flow. This set is intended for diesel mechanics and owners of Dodge Ram trucks and other vehicles equipped with the 5.9L 12V Cummins engine.

Key Features & Performance

• Bent and flared to OEM specifications for leak-free sealing
• Constructed from heavy-duty steel tubing to withstand high injection pressures
• Includes both injector line assemblies matching OEM 3960783 and 3960784
• Direct bolt-on replacement—no modifications required on factory fuel systems
• Restores idle quality and acceleration by ensuring even fuel delivery
• Corrosion-resistant coating for long service life

Fitment & Compatibility

• Fits 1989, 1990, and 1991 Cummins 12V 5.9L diesel engines
• Compatible with Dodge Ram 2500/3500 trucks equipped with the 5.9L 12V Cummins
• Replaces OEM fuel injector line part numbers 3960783 (cylinder #1) and 3960784 (cylinder #2)

Common Uses

• Replacing cracked or leaking fuel injector lines on 12V Cummins engines
• Restoring fuel delivery after injector replacement or pump work
• Routine maintenance of 1989–1991 Dodge Ram diesel trucks
• Engine rebuilds and performance restoration projects

Technical Specifications

• Part Number(s): 3960783, 3960784
• Engine Application: 1989–1991 Cummins 12V 5.9L
• Line Material: Steel tubing
• Quantity: 2 lines (cylinders #1 and #2)

Frequently Asked Questions

Q: Do these injector lines come pre-formed for a 1990 Cummins 5.9L? A: Yes, they are manufactured to the exact bends of the OEM lines for 1989–1991 12V 5.9L engines and install without bending.

Q: Can I use these lines on a 1992 Cummins engine? A: No, these are specifically designed for 1989–1991 engines; the 1992+ 12V engines use different line routing and part numbers.

Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.