Do I need a FASS lift pump without a performance tune?

On CP4-equipped trucks — 2019+ Cummins 6.7, 2011+ Duramax LML, 2019+ Power Stroke 6.7 — a FASS lift pump is a strong recommendation even at stock power. CP4 failure is triggered by aeration, not power level. Trucks with CP3 injection pumps are more tolerant, but still benefit from FASS.

Does FASS lift pump installation require cutting or welding?

No. FASS Titanium Series installations are a bolt-on process — frame-mounted using existing bolt holes or provided hardware, no cutting or welding required. Fully reversible. Installation takes 3–5 hours on most platforms and does not require tank removal or modification.

What is the difference between FASS and AirDog diesel lift pumps?

Both FASS and AirDog provide air separation, water separation, and pre-filtration via frame-mounted systems. We install FASS as our standard. FASS uses centrifugal air separation with integrated water separator and filter in a single housing. Both are capable systems — we standardize on FASS for installation consistency and filter supply.

FASS Titanium fuel lift pump installed diesel truck Houston Drop Forged Diesel

FASS Authorized Installer · Houston, TX

FASS FUEL
SYSTEMS
HOUSTON

FASS Titanium Series lift pump installation for Cummins, Power Stroke, and Duramax — the lift pump on every performance diesel build we do.

Why FASS on Every Build

THE LIFT PUMP
IS THE
FIRST UPGRADE.

Every diesel performance build we do starts with the fuel system. Not the tune, not the turbo — the fuel system. The in-tank lift pump that came from the factory is designed to supply a factory injection pump at factory fuel demand. The moment you add a performance tune, you increase demand at the high-pressure injection pump inlet.

FASS Titanium Series lift pumps are frame-mounted, meaning they stay cooler, deliver fuel at consistent pressure regardless of tank level, and remove both air and water from the fuel stream before it reaches the CP3 or CP4. Air in the fuel line is the leading cause of CP4 failure — the CP4's lubrication depends entirely on fuel, and aerated fuel provides no lubrication at high-pressure contact surfaces.

We install FASS on every diesel build that carries a performance tune. On trucks with a CP4 injection pump — 2019+ Cummins, 2011+ Duramax LML, 2019+ Power Stroke 6.7 — the FASS goes in before the tune, not alongside it. See the fuel system upgrades page for the full fuel system build sequence and the engine tuning page for how lift pump installation fits into the overall build order.

FASS also integrates a particulate pre-filter and water separator — the two other fuel contaminants that damage injection components. In Texas, where summer fuel temperatures can spike and condensation in fuel tanks is common, the water separator pays for itself in injector life alone.

FASS Titanium Series diesel lift pump Houston

FASS Series We Install

Choosing the Right FASS for Your Build

FASS flow ratings are matched to the fuel demand of the build — turbo configuration, injector size, and tune stage all factor into the selection.

FASS 150

150 GPH · Titanium Series

The FASS 150 is the correct lift pump for Stage 1 and Stage 2 single-turbo builds with stock or mildly upgraded injectors. 150 GPH provides sufficient lift pump capacity for CP3 or CP4 inlet demand at Stage 2 fuel flow without over-sizing. It is the standard lift pump for most street builds.

Cummins 6.7 — Stage 1/2

Duramax LML — Stage 1/2

Power Stroke 6.7 — Stage 1/2

Most Common

FASS 165

165 GPH · Titanium Series

The FASS 165 is our most frequently installed lift pump — the right choice for Stage 2 and Stage 3 single-turbo builds with upgraded injectors (up to 30% over), and the minimum we recommend on CP3 conversion setups. The additional flow headroom over the 150 matters at sustained WOT with an upgraded fuel system.

Cummins 6.7 — Stage 2/3 + CP3

Duramax LBZ/LML — Stage 2/3

Power Stroke 6.7 — Stage 2/3 + CP3

FASS 220

220 GPH · Titanium Series

The FASS 220 is specified for compound turbo Stage 3 builds with 60% over injectors or larger, and for any competition application where fueling demand at WOT approaches the 165's capacity ceiling. Tow trucks running sustained WOT at heavy load on long grades also benefit from the 220's additional capacity.

Cummins 6.7 — Compound/Competition

Duramax — Stage 3 Competition

Any platform with 60%+ injectors

What FASS Actually Does

Four Functions in One Unit

FASS is not just a flow booster. Each function addresses a specific failure mode in diesel injection systems.

Consistent Inlet Pressure

Frame-mounted FASS pumps maintain consistent positive inlet pressure to the injection pump regardless of fuel tank level. Factory in-tank lift pumps lose pressure as the tank drains — a half-tank becomes an eighth-tank during a long pull, and the CP3 or CP4 is now working harder to pull fuel against lower head pressure. FASS eliminates the tank-level variable entirely.

Air Separation

Aerated fuel is the primary cause of CP4 high-pressure injection pump failure. The CP4 relies entirely on fuel for lubrication — air bubbles in the fuel stream reduce lubrication at the cam and plunger contact surfaces, creating metal wear. FASS uses a centrifugal separation stage to remove entrained air before fuel reaches the injection pump. This is the single most important function FASS provides on CP4-equipped trucks.

Water Separation

Water in diesel fuel is a real-world problem — condensation accumulates in fuel tanks, and commercial diesel quality varies. FASS integrates a water separator that pulls free water out of the fuel stream before it reaches the injectors. Water in diesel is not compressible — at injection pressures above 20,000 PSI, water causes injector tip erosion and potential hydraulic failure. The water separator drains via a petcock on the filter housing.

Particulate Pre-Filtration

FASS includes a 2-micron pre-filter upstream of the injection pump — significantly finer than the factory fuel filter. Modern common-rail diesel injection systems operate at tight clearances where even small particles cause wear. The FASS pre-filter catches contamination before it enters the high-pressure side. On trucks operating in dusty environments or using farm diesel, this filter earns its cost quickly.

Platform Reference

FASS Recommendation by Platform and Stage

Our standard FASS specification for each diesel platform by build stage.

Platform	Trucks	Stage 1	Stage 2	Stage 3 / Compound
Cummins 6.7	Ram 2500/3500 2007–Present	FASS 150	FASS 165 Rec	FASS 220
Cummins 5.9	Ram 2500/3500 1994–2007	FASS 95	FASS 150 Rec	FASS 165
Duramax LML	Silverado/Sierra 2500 2011–2016	FASS 150	FASS 165 Rec	FASS 220
Duramax LBZ	Silverado/Sierra 2500 2006–2007	FASS 95	FASS 150 Rec	FASS 165
Duramax L5P	Silverado/Sierra 2500 2017–Present	FASS 150	FASS 165 Rec	FASS 220
Power Stroke 6.7	F-250/F-350 2011–Present	FASS 150	FASS 165 Rec	FASS 220

Common Questions

FASS Lift Pump FAQ

Questions we hear regularly about FASS installation and when it's required.

Do I need a FASS lift pump if I'm not doing a performance tune?+

On CP4-equipped trucks — 2019+ Cummins 6.7, 2011+ Duramax LML, 2019+ Power Stroke 6.7 — a FASS lift pump is a strong recommendation even at stock power. The CP4's failure mode is catastrophic and is triggered by aeration, not by power level. A stock tune truck with aerated fuel is still at risk. For trucks with CP3 injection pumps at stock power levels, a lift pump is beneficial but less urgent — the CP3 is more tolerant of inlet conditions. We always have the conversation during consultation.

Does FASS installation require cutting or welding on the truck?+

No. FASS Titanium Series installations are a bolt-on process — the pump mounts to the frame rail using existing bolt holes or provided mounting hardware with no cutting or welding required. The fuel lines route from the tank (pickup tube) through the FASS unit and to the injection pump using supplied fittings. The installation is fully reversible. On most platforms, installation takes 3–5 hours. The pump does not require modification to the tank or removal of the factory in-tank pump on most applications.

What is the difference between FASS and AirDog lift pumps?+

Both FASS and AirDog are reputable frame-mounted lift pump systems that provide air separation, water separation, and pre-filtration. We install FASS as our standard lift pump. The primary functional differences are: FASS uses a centrifugal air separation design and integrates the water separator and filter in a single housing; AirDog uses a similar approach with slightly different filter servicing access. Both are capable systems — we carry FASS because we've standardized on it across our builds and have consistent installation experience and filter supply for it. If a customer specifically requests AirDog, we can discuss it during consultation.

How often does the FASS filter need to be replaced?+

FASS recommends filter replacement at 15,000–25,000 miles depending on fuel quality and operating conditions. The 2-micron pre-filter will load faster on trucks using farm diesel, off-road diesel, or operating in high-particulate environments. FASS filter kits are available as a scheduled maintenance item — we stock them and can service the FASS system during oil change intervals or at annual service. The water separator should be drained periodically by opening the petcock on the filter housing — check it at fuel-up if the truck operates in humid or condensation-prone conditions.