FASS DIFSL5P1001 Drop-In Series Fuel System | 2017-2024 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Features:

• Fits L5P Duramax applications
• True drop-in, no cutting or wiring required
• Removes over 99% of water from fuel
• 2 micron absolute filtration rating
• Eliminates air and vapor from diesel fuel
• Extends fuel system and injector life
• Improves throttle response and horsepower
• Optimizes MPG with cleaner fuel delivery
• Installs in under an hour
• Works with factory or billet filter caps
• Keeps factory in-tank lift pump in place
• 50-state legal – CARB EO # D-713-3

High-Performance Fuel System for GM 6.6L Duramax

If you’re driving an L5P Duramax, you already know the factory fuel filtration system leaves a lot to be desired—especially if you’re running your truck hard, towing regularly, or planning on keeping it long-term. The FASS Drop-In Series Fuel System was built to solve those problems without overcomplicating the install. It’s the first and only drop-in system designed specifically for the 2017–2024 Silverado and Sierra 2500HD/3500HD that offers full fuel filtration and air separation—and does it all while retaining your factory in-tank lift pump and water-in-fuel sensor. What really makes this system stand out is the Extreme Water Separator technology. It’s been third-party tested to remove more than 99% of both free and emulsified water, which is a huge deal considering how sensitive today’s high-pressure injection systems are to moisture. And if the filter reaches capacity, it acts as a safeguard—cutting off flow to prevent further damage rather than letting contaminated fuel make its way through your injectors. That kind of built-in protection can save you thousands in repairs down the line.

High-Quality Construction with Impressive Filtration

This system also filters down to 2 microns, which is a big improvement over stock and more than enough to trap the fine particles that can wear out pumps, injectors, and regulators. On top of that, it strips air and vapor from the fuel—something most systems completely ignore. Removing that entrained air can increase fuel lubricity by up to 10%, reduce injector noise, and even sharpen throttle response. Some drivers report improved MPG, but even if the numbers stay the same, the drivability and performance gains are hard to miss. Despite the serious performance benefits, FASS made this kit completely plug-and-play. No tuning adjustments, no cutting, no splicing wires—just bolt it in and go. It installs in under an hour for most mechanically inclined owners, and works with either the factory plastic cap or a billet filter cap if you’ve upgraded. Every connection uses OEM-style quick disconnects, so everything fits clean and stays serviceable down the road.

Fits: 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024 GM 6.6L Duramax

Application Note: THIS IS NOT A LIFT PUMP! This is an air separation/filtration system that utilizes your factory lift pump.

Install Instructions