CUMMINS 3957079 OEM FUEL RAIL SUPPLY LINE (CP3 TO RAIL) – RAM 5.9L (2003–2007)

Product Description

The Cummins 3957079 OEM Fuel Rail Supply Line is the direct high-pressure line that feeds fuel from the CP3 injection pump to the common rail on 2003–2007 5.9L Cummins engines. This genuine Cummins component is engineered to maintain proper pressure delivery, prevent internal leakage, and ensure long-term reliability under increased demand.

Failure of this line can cause hard starts, rail pressure loss, and injector performance issues. Installing a new **OEM** line ensures correct sealing at both the CP3 and rail, eliminating contamination risks often introduced by aftermarket alternatives.

FITMENT

• 2003–2007 Dodge Ram 2500/3500 with 5.9L Cummins
• Replaces CP3-to-Rail Supply Line on Common Rail engines

CROSS-REFERENCE & RELATED CUMMINS PARTS

• Cummins 3957912 Injector Line #1
• Cummins 3957911 Injector Line #2
• Cummins 3957074 Injector Line #3
• Cummins 3957073 Injector Line #4
• Cummins 3957910 Injector Line #5
• Cummins 3957069 Injector Line #6

FAQ

Is this an authentic Cummins OEM fuel rail supply line?

Yes — this is a genuine Cummins part, not aftermarket, ensuring proper sealing and pressure stability.

Should the supply line be replaced during CP3 or injector service?

Yes. Cummins recommends replacing high-pressure lines anytime they are loosened to avoid leaks and pressure loss.

What symptoms indicate a failing CP3-to-rail supply line?

Hard starting, rail pressure codes, surging, or visible fuel seepage at the line connections.

Does this line require torque-to-yield fittings?

No. It uses standard high-pressure sealing flare connections but must be torqued to factory specification.

Will this line fit 2007.5+ 6.7L Cummins trucks?

No — this part is only for 5.9L common-rail engines from 2003–2007.

SPECIFICATIONS