Unleash sustained fuel delivery in your Duramax with the Fleece CP3K—a purpose-built upgrade that removes the factory 3,000 RPM fuel-flow restriction and keeps your engine pulling hard when you need it most.

The CP3K is a meticulously engineered modification of the Duramax LBZ CP3, built around a brand-new Bosch CP3 core. By eliminating the stock pump’s fuel flow and rail pressure drop after the 3,000 RPM mark, this upgrade preserves your desired fuel rail pressure across the entire RPM band. The result? More consistent horsepower and confident power delivery when you’re towing, climbing grades, or hammering the throttle at higher RPMs.

Key benefits that matter on the road and track

• Maintains fuel rail pressure through the full RPM range, reducing power drop during high-demand moments
• Sharper throttle response and more reliable high-end performance for tuned Duramaxes
• Brand new Bosch CP3 core with no core charge, simplifying the upgrade path
• Cost-effective, high-impact upgrade that complements existing fuel systems and lift pumps
• Designed specifically to integrate with Duramax engines across multiple generations

Application notes and installation considerations

The CP3K is designed to fit a broad range of Duramax platforms. For 2001–2005 models (LB7 or LLY), the fuel pressure regulator requires appropriate scaling. Our application notes provide the necessary scaling values for these early trucks to ensure proper operation. This attention to regulator behavior is what keeps fuel delivery accurate across RPMs, rather than just delivering more fuel overall.

Compatibility and fitment

Fits GM Duramax diesel pickups and SUVs spanning 2001 through 2016, covering the following generations and configurations: LB7, LLY, LBZ, LMM, and LML variants. The CP3K is designed to align with the LBZ-LMM based architecture, delivering a robust upgrade path whether you’re running stock fueling or a tuned setup.

Who should consider the CP3K

• Owners pursuing steady, high‑rpm power without fuel starvation
• Enthusiasts building tuned or high‑flow Duramax setups who want reliable rail pressure at all throttle positions
• Trailers and heavy‑haul drivers who need consistent performance under load
• Shop technicians seeking a proven, no‑core‑charge CP3 upgrade with strong field support

Warranty and confidence

This product comes with a 1 Year Limited Parts Warranty, reflecting the build quality and durability you expect from Fleece Performance.