Product Description

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CUMMINS 3943769 OEM #3 FUEL INJECTION LINE – RAM 5.9L (1998.5–2002)

Keep your VP44-powered 1998.5–2002 Ram 5.9L Cummins sealed up and happy with a genuine Cummins 3943769 #3 fuel injection line. This high-pressure hard line connects the VP44 pump to the cylinder #3 injector using factory-correct bends and flare geometry, restoring precise fuel delivery and stopping leaks caused by vibration, fatigue, or over-tightened fittings.

Unlike generic copycat lines, this OEM tube is engineered by Cummins for the ISB 5.9L 24-valve platform, so it drops into the factory routing clips, torques correctly, and maintains the high injection pressures your VP44 system needs. Pair it with the full set of OE lines and return hardware from CPP Diesel for a complete, bulletproof fuel system refresh.

Key Features

• Genuine Cummins 3943769 #3 injector fuel supply tube (high-pressure hard line).
• Direct-fit for 1998.5–2002 Dodge Ram 2500/3500 5.9L ISB 24V with VP44 injection pump.
• Pre-formed with the correct length, radii, and flare geometry for leak-free sealing.
• Designed to resist vibration-induced cracking and fretting at clamps and fittings.
• Compatible with many Stage 2 ISB/QSB 5.9 industrial engines (always verify by ESN).
• Perfect match to the rest of the OEM injector line set and Cummins connector tubes.

Fitment – Automotive

• Engine: 5.9L ISB 24V Cummins (VP44)
• Model Years: 1998.5, 1999, 2000, 2001, 2002
• Chassis: Dodge Ram 2500 / Ram 3500
• Position: Cylinder #3 pump-to-injector high-pressure line

Fitment – Industrial / Off-Highway (General)

This tube is also used on select Stage 2 5.9L ISB/QSB engines in industrial, agricultural, and off-highway equipment. Always confirm compatibility by engine serial number (ESN) and Cummins parts catalog before ordering.

When to Replace Your #3 Injector Line

• Visible fuel dampness or wetness around the #3 line nuts or along the tube.
• Hard starts, rough idle, or haze after injector or VP44 pump replacement.
• Cracked, rusted, or previously bent OE line, especially near brackets and flares.
• Fuel system contamination (metal, rust, or water) where the entire high-pressure circuit is being renewed.

Cross-Reference & Companion Cummins Parts (CPP Diesel)

Refresh the entire VP44 fuel line set and supporting hardware with other genuine Cummins parts available from CPP Diesel:

• #1 Injector Line – CUMMINS 3943765 OEM FUEL INJECTION LINE – CYLINDER #1 – RAM 5.9L 24V (1998.5–2002)
• #2 Injector Line – CUMMINS 3943767 OEM FUEL INJECTION LINE #2 – RAM 5.9L 24V (1998.5–2002)
• #4 Injector Line – CUMMINS 3943771 OEM FUEL INJECTION LINE #4 – RAM 5.9L (1998.5–2002)
• #5 Injector Line – CUMMINS 3943773 OEM #5 FUEL INJECTION LINE – RAM 5.9L 24V (1998.5–2002)
• #6 Injector Line – CUMMINS 3943775 OEM #6 FUEL INJECTION LINE – RAM 5.9L (1998.5–2002) VP44
• Injector Connector Tube – CUMMINS 3936953 OEM FUEL INJECTOR CONNECTOR TUBE – RAM 5.9L (1998.5–2002)
• Return Line Tee – CUMMINS 3905353 OEM FUEL RETURN LINE TEE FITTING – RAM 5.9L 24V VP44 (1998.5–2002)
• VP44 Return Tube – CUMMINS 3945707 OEM FUEL DRAIN TUBE (VP44 RETURN LINE) – RAM 5.9L (1998.5–2002)
• Fuel Return Line to Tank – CUMMINS 3942592 OEM FUEL DRAIN TUBE / FUEL RETURN LINE (TO TANK) – RAM 5.9L 24V (1998.5–2002)
• Head-to-Tee Return Line – CUMMINS 3942966 OEM FUEL RETURN LINE (CYLINDER HEAD TO TEE) – RAM 5.9L 24V (1998.5–2002)

What’s In The Box

• (1) Genuine Cummins #3 fuel injection line – part number 3943769
• Line clamps, brackets, and related hardware are reused or purchased separately.

Installation Notes

• Match the new line’s routing to the original; do not twist, kink, or re-bend the tube.
• Keep all high-pressure connections extremely clean – cap open lines and injector inlets during service.
• Start flare nuts by hand at both the VP44 pump and injector to avoid cross-threading.
• Tighten to the factory torque specification; after warm-up and test drive, recheck for any signs of seepage.
• If one line cracked from age or vibration, inspect the remaining lines and clamps and consider replacing the full set.

Specifications for cummins 3943769

FAQ

WILL THIS FIT MY 1998.5–2002 5.9L 24-VALVE RAM?

Yes. This line is the OE cylinder #3 injector fuel supply tube for 1998.5–2002 Dodge Ram 2500/3500 5.9L ISB 24V trucks equipped with the VP44 injection pump. As always, confirm fitment by VIN or engine serial number (ESN) if components have been changed.

IS THIS A GENUINE CUMMINS PART OR AFTERMARKET?

This is a genuine Cummins 3943769 hard line, not a white-box copy. You get factory-correct geometry, materials, and flare design to maintain proper injection pressure and sealing.

DOES THIS LINE SERVE ANY CYLINDER OTHER THAN #3?

No. Each cylinder on the VP44 5.9L platform uses its own unique, pre-bent line. Part number 3943769 is specific to cylinder #3. Use the matching Cummins part numbers for cylinders #1, #2, #4, #5, and #6.

SHOULD I REPLACE ALL SIX LINES AT THE SAME TIME?

It isn’t strictly required, but if one line has cracked from age, corrosion, or vibration, the others are often not far behind. Many shops choose to install a full set of genuine Cummins lines to restore reliability and reduce repeat labor.

WHAT ELSE SHOULD I CHECK OR REPLACE DURING INSTALLATION?

Inspect and replace any worn line clamps or brackets, verify that the injector connector tubes and seals are in good condition, and follow proper torque and cleanliness procedures. After installation, prime the fuel system, warm the engine up, and recheck all connections for leaks.