FITMENT
- 2011-2016 6.6L Chevy GM Silverado Sierra Duramax LML 2500 3500 engine.
DESCRIPTION
Product Overview
- The GM Duramax 6.6L LML engine came equipped from the factory with a Bosch CP4.2 high-pressure fuel pump. The CP4 pump is notoriously prone to sudden, catastrophic mechanical failure—often referred to as "grenading." When a CP4 fails, it metal-contaminates the entire fuel system (injectors, rails, lines, and tank), leading to thousands of dollars in repairs.
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The CP3 Injection Pump Conversion Kit completely eliminates the problematic CP4 pump by converting your LML fuel system back to the battle-tested, high-reliability Bosch CP3 injection pump platform. This upgrade restores long-term engine reliability, maintains smooth fuel delivery, and supports both stock and high-performance tuning applications without the risk of fuel system contamination.
Key Features
- Precision CNC Machined Brackets: Includes high-strength billet aluminum adapter plates and mounting hardware designed for a factory-like fit in the LML engine valley.
- High-Flow Fuel Delivery: Delivers consistent high-pressure fuel flow to handle everything from stock daily driving and heavy towing to high-horsepower aftermarket tuning.
- Eliminates CP4 Pump Failure Risk: Replaces the fragile stock CP4 pump with a ultra-durable CP3 high-pressure pump, protecting your injectors and fuel system from catastrophic metal contamination.
- Maintains Factory Emissions Components: Engineered to fit smoothly under the stock intake manifold and around factory wiring harnesses without requiring custom fabrications.
FAQ
Q: Why is the factory Bosch CP4 pump on the Duramax LML considered a ticking time bomb?
A: The stock CP4.2 pump relies entirely on diesel fuel for internal lubrication. Because US Ultra-Low Sulfur Diesel (ULSD) has poor lubricity, CP4 metal rollers often wear out, tilt, and grind against the camshaft, creating thousands of microscopic metal shavings that get pumped throughout your entire fuel system.
Q: Why is a CP3 conversion better than just adding a CP4 "Disaster Prevention/Bypass Kit"?
A: A disaster kit is only a "band-aid"—it keeps the fragile CP4 pump in place and merely reroutes contaminated return fuel to prevent ruining the tank, but your CP4 will still eventually explode and leave you stranded on the road. A CP3 conversion kit cures the disease by removing the unreliable CP4 pump permanently.
Q: Is it better to install this CP3 kit proactively, or wait until my factory CP4 pump fails?
A: Proactively, without a doubt. If you wait for the CP4 to fail, you will have to replace all 8 injectors, high-pressure fuel rails, lines, and drop the fuel tank to flush out metal shavings. Converting before a failure means you only swap the pump hardware, saving thousands in clean-up labor and parts.
Q: Can I install this CP3 conversion kit if my factory CP4 pump has ALREADY failed and contaminated the system?
A: While this kit replaces the failed pump, if your CP4 has already "grenaded," you must thoroughly flush or replace the entire fuel system (including the fuel tank, fuel lines, high-pressure fuel rails, and injectors) before installing the new CP3 pump and conversion kit to prevent trapped metal shavings from destroying your new setup.
