Product Description
Delete the CP4 weak link on your LML and step up fueling headroom with INDUSTRIAL INJECTION’s CP4→CP3 conversion that includes a 42% over “SHO” CP3. This kit is built for serious power goals and competition use where increased rail capacity and reliability are mandatory.
Fitment
- 2011–2016 Chevrolet Silverado / GMC Sierra 2500HD & 3500HD — 6.6L Duramax LML
What’s Included
- Industrial Injection 42% over “SHO” CP3 high-pressure pump
- Application-specific brackets, adapter lines/fittings, and hardware
- Electrical provisions / harness extensions as required
- Install instructions
Why This Kit
- Reliability upgrade: Replaces failure-prone CP4 with proven CP3 architecture
- 42% over fueling: Supports elevated rail demands and bigger injector/turbo setups
- Clean install: OE-style fitment with purpose-built lines, brackets, and wiring
Recommended Parts (CPP Internal Links)
- FASS DMAX7002 Lift Pump — 2011–2016 LML
- AirDog LML Lift Pump Options
- Dorman 904-000 Fuel Filter Housing — LML
- Alternate: II 436401 CP3 Conversion (emissions-intact, with pump)
- Alternate: S&S LML-CP3-CARB (50-state, no-tune)
- Alternate: S&S LML-CP3-TUNING-REQ (competition)
- Shop All GM Duramax Categories
Cross-Reference / Alternatives
- II 436401 — CP3 Conversion w/ Pump (emissions-intact, no-tune)
- II 436408 — Dual Fueler Kit (adds second CP3)
- S&S LML-CP3-CARB — CARB-exempt, no-tune
Helpful Notes
- Tuning: A 42% over CP3 typically requires custom calibration to command/maintain rail pressure under load.
- Emissions/legality: Verify local laws. For on-road use needing CARB, see the S&S 50-state kit above.
- Best practice: Add a quality lift pump and fresh filtration after conversion to protect injectors and the CP3.
FAQ
Does this 42% over kit require tuning?Yes—bigger CP3 output generally needs custom tuning to properly control rail pressure and fueling on the LML.
Is this emissions-intact / CARB legal?This performance-oriented kit is intended for off-road/competition. If you need a 50-state legal solution with no tuning, see the S&S CARB-exempt kit linked above.
What lift pump should I run with a CP3 conversion?A FASS or AirDog system sized for your power goal stabilizes supply pressure, improves filtration, and extends CP3 and injector life.
What’s the difference vs. II 436401?436401 is a CP3 conversion with pump designed to run on stock calibration and emissions-intact trucks. 436404 adds a 42% over SHO pump for higher output, typically with tuning and competition use.
