Best Inline Fuel Pumps for EFI Applications

As an enthusiast who’s spent countless hours wrenching on everything from daily drivers to weekend track warriors, I’ve learned that a reliable fuel system is the heart of any performance vehicle, especially when we’re talking about modern Electronic Fuel Injection (EFI) applications. There’s nothing quite as frustrating as chasing down a fuel delivery issue when you’re trying to get that perfect tune or just enjoy a spirited drive. That’s why diving deep into the world of inline fuel pumps for EFI applications is so crucial. A good quality pump ensures consistent fuel pressure and flow, which directly translates to better engine performance, reliability, and peace of mind.

IMAGE	PRODUCT NAME	AMAZON LINK
	GSL392 Inline Fuel Pump & 58 PSI Fuel Filter Regulator…	View on Amazon
	EVIL ENERGY External Inline Fuel Pump Electric 300LPH High…	View on Amazon
	Holley 12-927 43 GPH Inline Electric Fuel Pump – Efi…	View on Amazon
	Holley 12-170 100 GPH Universal In-line Electric Fuel Pump	View on Amazon
	High Flow Pressure External Inline 255LPH Fuel Pump With…	View on Amazon
	Trexflow TF 2225 Fuel Pump 45 GPH 60 Psi IN…	View on Amazon
	EVIL ENERGY External Inline Fuel Pump Electric 300LPH High…	View on Amazon
	YOMIRACING High-Pressure Inline Fuel Pump 255LPH (Universal…	View on Amazon
	A-Premium Universal External Pump 255LPH High Pressure…	View on Amazon
	BREADEEP Universal External Inline Fuel Pump Electric High…	View on Amazon

I’ve seen firsthand how a poorly matched or cheap fuel pump can cause headaches, from lean conditions that risk engine damage to simply not having enough fuel to hit your power goals. That’s why I’ve rounded up ten of the most popular and promising inline fuel pumps for EFI applications on the market today. My goal here isn’t just to list features; it’s to give you a practical, real-world perspective on what each pump offers, who it’s best for, and what to expect when you’re bolting it onto your pride and joy. Let’s dig in and find the perfect pump for your next project, ensuring your EFI system gets the reliable fuel supply it deserves.

1. GSL392 Inline Fuel Pump & 58 PSI Fuel Filter Regulator Kit

This GSL392 kit is an absolute lifesaver if you’re tackling an LS swap or any EFI conversion that specifically calls for a 58 PSI returnless fuel system. What sets it apart is the integrated fuel filter regulator, which drastically simplifies your plumbing. Instead of piecing together separate components, you get a clean, combined unit that delivers a rock-solid 58 PSI to your fuel rail and sends unused fuel back to the tank. The included 255 LPH GSL392 pump is a proven workhorse, capable of supporting a good amount of horsepower, especially in boosted applications, making it a popular choice for performance upgrades. It also comes with the necessary 6AN adapter fittings, which is a huge convenience, minimizing trips to the parts store.

• Key Features:

  • Integrated 58 PSI fuel filter regulator with 10-micron filter
  • GSL392 high-pressure 255 LPH fuel pump (flows over 210 LPH at 80 PSI)
  • Includes 6AN adapter fittings for LS Swap and EFI conversion
  • Designed for turbo and supercharged EFI applications
  • OEM-style design for direct fitment in many common applications

• Pros:

  • All-in-one solution significantly simplifies LS swap fuel systems
  • Reliable 58 PSI pressure for consistent EFI performance
  • Includes essential fittings, saving time and hassle
  • Good flow rate for many performance builds
  • Durable construction

• Cons:

  • Fixed 58 PSI output isn’t suitable for all EFI systems
  • Pump is externally mounted, requiring proper placement and protection
  • Specific fitment for LS-based engines might limit universal application

• Best for: LS engine swaps and EFI conversions requiring a 58 PSI returnless fuel system.

• User feedback summary: Users universally praise the convenience and simplicity of this kit for LS swaps, often highlighting how it eliminates the guesswork of matching a regulator and filter, leading to reliable and consistent fuel pressure.

2. EVIL ENERGY External Inline Fuel Pump Electric 300LPH High Flow

When your EFI application demands serious fuel flow, the EVIL ENERGY 300LPH pump steps up to the plate. This pump is a beast, pushing up to 300 liters per hour at 13.5V and 43 PSI, making it suitable for high-horsepower builds where a 255 LPH pump just won’t cut it. What I particularly like is its broad fuel compatibility, handling everything from gasoline and race gas to diesel, E85, and other alcohols. This makes it incredibly versatile for those running flex-fuel setups or pushing the limits with alternative fuels. Installation is straightforward with included instructions, though they recommend mounting it below the tank for gravity feeding, which is good practice for any external pump to prevent cavitation.

• Key Features:

  • High test flow rates: 255 LPH (43 PSI/12V) / 300 LPH (43 PSI/13.5V)
  • Operating pressure up to 75 PSI
  • Compatible with gasoline, race gas, diesel, E85, and alcohol/ethanol
  • Wide operating temperature range (-68 °F to 194 °F)
  • Designed for 12V DC EFI systems only

• Pros:

  • Excellent high flow for demanding performance applications
  • Fully compatible with E85 and other corrosive fuels
  • Robust construction for durability
  • Good value for its performance level
  • Comes with installation instructions

• Cons:

  • Recommended below-tank installation can be challenging depending on vehicle
  • High flow might be overkill for milder EFI setups
  • Requires a separate fuel pressure regulator

• Best for: High-performance EFI builds, particularly those running E85 or needing substantial fuel flow.

• User feedback summary: Owners frequently report impressive flow rates and strong, consistent pressure from this pump, making it a popular choice for upgraded turbos and superchargers, with many appreciating its E85 compatibility.

3. Holley 12-927 43 GPH Inline Electric Fuel Pump – EFI Ready

Holley is a name synonymous with fuel systems, and their 12-927 inline pump is a solid choice for entry-level EFI conversions, especially those using a throttle body EFI (TBI) unit. Don’t expect it to feed a monstrous twin-turbo setup, but for its intended purpose, it’s reliable and efficient. It flows 43 GPH at 15 PSI, which is plenty to support up to 400 horsepower with a TBI system. One of its standout features is the remarkably low current draw of just 3.5 amps, making it easy on your electrical system. The kit includes 3/8″ barbed fittings, a rubber isolator, mounting clamps, and electrical hardware, so you’re ready to go out of the box. This is a great no-frills option if you’re upgrading an older carbureted engine to basic EFI.

• Key Features:

  • Flows 43 GPH at 15 PSI
  • Low current draw: 3.5 amps at 15 PSI
  • Supports up to 400 horsepower throttle body EFI units
  • Includes 3/8″ barbed fittings
  • Comes with rubber isolator, mounting clamps, and electrical hardware

• Pros:

  • Excellent reliability from a trusted brand
  • Very low power consumption
  • Easy to install with included hardware
  • Perfectly suited for TBI EFI conversions
  • Quiet operation

• Cons:

  • Not designed for multi-point EFI systems
  • Lower flow rate limits its use in high-horsepower applications
  • Barbed fittings might not be preferred by all users

• Best for: Throttle body EFI (TBI) conversions up to 400 horsepower, basic EFI upgrades.

• User feedback summary: Many users appreciate the straightforward installation and the pump’s quiet, consistent performance when converting older carbureted engines to simple TBI EFI, noting its dependability for its specific application.

4. Holley 12-170 100 GPH Universal In-line Electric Fuel Pump

Stepping up significantly in performance from the previous Holley offering, the 12-170 is built for serious enthusiasts. This universal inline pump delivers a hefty 100 GPH, capable of supporting up to 900 naturally aspirated EFI horsepower or 700 boosted EFI horsepower. It features a robust roller vane design, known for its durability and consistent performance. What’s truly impressive is its PWM (Pulse Width Modulation) compatibility, allowing for precise fuel delivery control, which is great for advanced EFI systems. It’s also fully Flex Fuel (E85/E90) compatible, a must-have for modern performance builds. The use of -8 AN female ORB for the inlet and -6 AN ORB for the discharge, along with included fittings and a check valve, means high-quality, leak-free connections.

• Key Features:

  • Flows 100 GPH
  • Supports up to 900 EFI N/A or 700 EFI Boosted horsepower
  • Durable roller vane design
  • PWM compatible for precise control
  • Flex Fuel (E85/E90) compatible
  • -8 AN female ORB inlet and -6 AN ORB discharge fittings

• Pros:

  • High flow rate for very high-horsepower applications
  • E85 compatibility for modern performance fuels
  • PWM support allows for advanced fuel system integration
  • Robust and reliable roller vane pump design
  • High-quality AN ORB connections for leak-free sealing

• Cons:

  • Premium price point
  • Overkill for mild or stock EFI systems
  • Requires a high-quality fuel pressure regulator to match its output

• Best for: High-output naturally aspirated and forced induction EFI vehicles with significant horsepower requirements.

• User feedback summary: Performance builders consistently praise the Holley 12-170’s immense flow and rock-solid pressure even under extreme conditions, highlighting its reliability for high-horsepower, E85-fueled engines as a key advantage.

5. High Flow Pressure External Inline 255LPH Fuel Pump With Installation Kit (GSL392 Type)

This external inline fuel pump is another take on the popular GSL392 255 LPH design, a staple in the performance aftermarket. It’s a universal pump, meaning it fits a wide range of vehicles and EFI applications, including turbo and supercharged setups, supporting up to 650 horsepower. The all-metal shell for both the inlet and outlet speaks to its durability, which is crucial for a component handling pressurized fuel. It boasts a wide operating pressure range from 15-120 PSI (though your regulator will set the final pressure), offering flexibility. Crucially, it’s compatible with gasoline, pump gas, race gas, diesel, E85, and alcohol/ethanol, making it a versatile choice for many performance enthusiasts looking for a reliable, high-flow external pump without the integrated regulator of some kits. It also comes with a basic installation kit, which is a nice touch.

• Key Features:

  • 255 LPH flow rate
  • Supports up to 650 horsepower
  • All-metal shell construction
  • Compatible with gasoline, E85, diesel, and alcohol/ethanol
  • Universal fitment for most EFI applications (turbo/supercharged friendly)
  • Includes mounting clamps and cushion, electrical connectors

• Pros:

  • Proven flow rate for a broad range of modified engines
  • Excellent fuel compatibility, including E85
  • Durable, all-metal construction
  • Good value for the performance offered
  • Comes with basic installation hardware

• Cons:

  • Does not include a fuel pressure regulator, which must be purchased separately
  • Requires proper wiring for its 20 amp draw
  • External mounting requires careful placement and protection

• Best for: Modified vehicles needing a reliable 255 LPH external pump, especially those running E85 or other alternative fuels.

• User feedback summary: Users often choose this pump as a direct and cost-effective upgrade for their modified EFI systems, frequently praising its consistent fuel delivery and ability to support significant horsepower in both naturally aspirated and boosted applications.

6. Trexflow TF 2225 Fuel Pump 45 GPH 60 Psi IN-Line Electric

The Trexflow TF 2225 offers a compelling blend of performance and affordability, making it an excellent option for more moderate EFI systems or as a “booster” pump. Flowing 45 GPH at 60 PSI, it’s capable of supporting multi-port EFI systems up to 525 horsepower. This positions it well for many V8 swaps or mild-to-moderate performance builds where you don’t need the extreme flow of a 255 or 300 LPH pump but still require solid EFI pressure. What’s reassuring is its ISO 9001 & IATF 16949 certification, indicating a commitment to quality control in its manufacturing. The 3/8″ hose nipple inlet and outlet make it easy to plumb into existing fuel lines, although some enthusiasts prefer AN fittings for a more secure connection.

• Key Features:

  • Flows 45 GPH at 60 PSI (translates to good flow for EFI)
  • Supports multi-port EFI systems up to 525 HP
  • Can be used as a “booster” for nitrous applications
  • 3/8″ hose nipple inlet and outlet
  • ISO 9001 & IATF 16949 Certified quality

• Pros:

  • Cost-effective solution for mid-range EFI performance
  • Versatile as a standalone or booster pump
  • Good quality control certifications
  • Easy to install with hose barb connections
  • Consistent pressure delivery for its rating

• Cons:

  • Hose barb fittings might not be preferred for all high-pressure setups
  • Lower flow than 255/300 LPH pumps, limiting very high HP builds
  • Requires a separate fuel pressure regulator

• Best for: Moderate multi-port EFI systems up to 525 HP, or as a reliable booster pump for performance setups.

• User feedback summary: Owners consistently point to the Trexflow 2225’s excellent value, often noting its reliable pressure and sufficient flow for their 400-500 HP EFI builds without the higher price tag of premium brands.

7. EVIL ENERGY External Inline Fuel Pump Electric 300LPH High Flow (Performance Version)

Yes, we’re looking at another iteration of the EVIL ENERGY 300LPH pump, a testament to its popularity and effectiveness in the aftermarket. This specific listing emphasizes its high-flow performance for demanding 12V DC EFI systems. As before, it boasts impressive test flows – up to 300 LPH at 13.5V and 43 PSI, with an operating pressure up to 75 PSI – making it a serious contender for power-hungry engines. Its standout feature remains its universal compatibility with a wide range of fuels, including gasoline, diesel, E85, and other alcohols, which is essential for performance tuners and those exploring alternative fuels. The recommendation for below-tank installation is key for optimal performance and pump longevity, ensuring a steady, gravity-fed supply.

• Key Features:

  • Specifically for 12V DC electric injection systems
  • High test flow: up to 300 LPH (at 13.5V & 43 PSI)
  • Operating pressure up to 75 PSI
  • Wide fuel compatibility: gasoline, E85, alcohol/ethanol, diesel
  • Broad operating temperature range (-68 °F to 194 °F)
  • Includes installation instructions

• Pros:

  • Exceptional high flow rate for high-horsepower EFI applications
  • Outstanding compatibility with various performance fuels, including E85
  • Durable and robust construction for long-term reliability
  • Consistent performance even under demanding conditions
  • A cost-effective alternative to higher-priced high-flow pumps

• Cons:

  • Requires a dedicated fuel pressure regulator (not included)
  • Optimal performance relies on proper installation, ideally below the fuel tank
  • Flow might be excessive for stock or lightly modified EFI systems

• Best for: Serious high-performance EFI builds where maximum fuel flow and E85 compatibility are paramount, offering a proven, reliable option.

• User feedback summary: Consistent feedback highlights the Evil Energy 300LPH’s robust output and reliability for demanding performance builds, with many users praising its ability to maintain consistent pressure under high boost and its E85 compatibility as a major plus.

8. YOMIRACING High-Pressure Inline Fuel Pump 255LPH (Universal)

The YOMIRACING 255 LPH High-Pressure Inline Fuel Pump is another solid entry in the universal GSL392-style pump category. It’s built with premium all-metal construction, ensuring durability and resistance to wear and tear from fuel. This pump is designed to support up to 650 horsepower, making it a fantastic upgrade for a wide array of modified vehicles, from street cars to track machines. With a flow rate of 255 LPH and a 20 AMP draw, it delivers consistent fuel to your EFI system. It comes with a 10mm x 1mm threaded inlet/outlet, which is standard for many inline pumps, and thoughtfully includes two universal 5/16″ barb fittings to help with common installations. Its broad compatibility with most EFI systems, including turbocharged and supercharged setups, makes it a versatile and dependable choice.

• Key Features:

  • Premium all-metal construction (inlet and outlet)
  • 255 LPH flow rate with 20 AMP draw
  • Supports up to 650 horsepower
  • 10mm x 1mm threaded inlet/outlet with two included 5/16″ barb fittings
  • Compatible with most EFI systems (turbocharged/supercharged friendly)
  • Universal fitment, direct replacement for GSL392 part numbers

• Pros:

  • Durable, all-metal construction for longevity
  • High-performance capabilities for up to 650 HP
  • Universal fitment for broad application
  • Comes with common barb fittings for easier installation
  • Good value for its flow and build quality

• Cons:

  • Fuel pressure regulator is not included
  • 5/16″ barb fittings might be undersized for some extreme high-flow setups
  • Requires proper wiring for its 20 amp draw

• Best for: Modified EFI vehicles up to 650 HP seeking a robust, universal 255 LPH pump from a reliable aftermarket supplier.

• User feedback summary: Many users consider the YOMIRACING pump a reliable and affordable alternative to other 255 LPH options, often noting its solid construction and consistent pressure delivery in their high-performance EFI projects.

9. A-Premium Universal External Pump 255LPH High Pressure Inline Fuel Pump Kit (GSL392)

The A-Premium Universal External Pump offers a comprehensive solution for those looking for a 255 LPH GSL392-style pump with a complete installation kit. This is a huge benefit, as it means you won’t be scrambling for small parts during your build. The kit includes the GSL392 255 LPH fuel pump (20 AMP), a foam insulation sleeve, mounting clamps, copper crush washers, eyelet terminals, electrical nuts, star washers, and two 10mm to 3/8″ barb fittings. It specifically highlights its suitability for LS Returnless 6AN Engine Swaps, which is a popular application. This pump is a solid performer for most EFI applications, including turbo and supercharged setups, delivering consistent fuel pressure and flow. The inclusion of all the bits and pieces makes this kit a very appealing “grab-and-go” option for many DIYers.

• Key Features:

  • GSL392 255 LPH fuel pump (20 AMP)
  • Comprehensive installation kit included (foam sleeve, clamps, washers, terminals, fittings)
  • Specifically compatible with LS Returnless 6AN Engine Swaps
  • Suitable for most EFI applications, including turbo and supercharged
  • Flows 255 Liters Per Hour

• Pros:

  • Complete kit provides excellent value and convenience for installation
  • Reliable 255 LPH flow for many performance applications
  • Includes necessary hardware and fittings, reducing extra purchases
  • Good choice for LS swaps needing a GSL392-style pump
  • Durable and dependable performance

• Cons:

  • Does not include a fuel pressure regulator (if not using an integrated filter/regulator setup)
  • Warning about needing professional knowledge implies it’s not for absolute beginners
  • Barb fittings might require hose clamps for security

• Best for: DIY enthusiasts undertaking LS swaps or general EFI conversions who need a complete 255 LPH pump kit with all the necessary installation hardware.

• User feedback summary: Customers frequently commend the completeness of this kit, stating it simplifies their EFI and LS swap projects by providing everything needed for installation, and appreciate its reliable performance.

10. BREADEEP Universal External Inline Fuel Pump Electric High Flow 300LPH

Rounding out our list is another high-flow contender, the BREADEEP Universal External Inline Fuel Pump, offering an impressive 300 LPH of fuel delivery. This pump is geared towards serious performance, with test flows up to 300 LPH at 13.5V and 43 PSI, and a high operating pressure of 75 PSI. Like other top-tier options, it boasts excellent fuel compatibility, working flawlessly with gasoline, race gas, diesel, E85, and alcohol/ethanol. What makes this particular offering stand out is its comprehensive packing list, including not just the pump and mounting bracket, but also AN8 to M121.5 and AN10 to M121.5 adapters, rubber connection covers, insulated terminals, gaskets, nuts, and even an outlet check valve. This level of included hardware provides exceptional flexibility for plumbing into diverse fuel systems, offering a lot of bang for your buck.

• Key Features:

  • High flow rates: 255 LPH (43 PSI/12V) / 300 LPH (43 PSI/13.5V)
  • Operating pressure up to 75 PSI
  • Compatible with gasoline, E85, alcohol/ethanol, diesel
  • Comprehensive packing list with AN8/AN10 adapters, mounting bracket, etc.
  • Recommended for installation underneath the tank

• Pros:

  • Very high flow for extreme performance EFI applications
  • Extensive fuel compatibility, including E85
  • Includes a generous selection of AN adapters and installation hardware
  • Durable construction and wide operating temperature range
  • Great value for a high-flow pump with included fittings

• Cons:

  • High flow may be overkill for less aggressive builds
  • Optimal performance requires careful, often below-tank, installation
  • Requires a separate high-quality fuel pressure regulator

• Best for: Performance enthusiasts building high-horsepower EFI systems, especially those using E85, who value a complete kit with versatile AN adapters for easier plumbing.

• User feedback summary: Users often highlight the BREADEEP pump’s impressive flow and the value of its extensive included hardware, noting that the AN adapters greatly simplify installation into various custom fuel systems while providing ample fuel for highly modified engines.

Helpful Comparison Insights

When you’re looking at inline fuel pumps for EFI applications, you’ll notice a few key differentiators. First, let’s talk about flow rate, measured in Liters Per Hour (LPH) or Gallons Per Hour (GPH). For milder EFI setups or Throttle Body Injection (TBI) conversions, pumps like the Holley 12-927 (43 GPH) or Trexflow TF 2225 (45 GPH) are often sufficient, supporting up to around 400-500 horsepower. These are great for straightforward upgrades and tend to be more budget-friendly.

Stepping up, the 255 LPH (approx. 67 GPH) pumps like the GSL392 variants from YOMIRACING, A-Premium, and the bundled kit from GSL392 Inline Fuel Pump & 58 PSI Fuel Filter Regulator are the workhorses of the performance EFI world. They support a wide range of modified engines, often up to 600-650 horsepower, and are a very popular upgrade. Their appeal comes from a good balance of flow, reliability, and cost. Many of these are E85 compatible, which is a crucial consideration for modern performance fuels.

For those pushing serious power, 300 LPH (approx. 79 GPH) pumps from EVIL ENERGY and BREADEEP are designed for high-horsepower, boosted, or aggressively tuned EFI systems. They offer the extra headroom needed for 700+ horsepower, especially when using E85 which requires a higher volume of fuel.

Another major point is integration. The GSL392 Inline Fuel Pump & 58 PSI Fuel Filter Regulator kit stands out by combining the pump, filter, and a fixed 58 PSI regulator, making it an all-in-one solution particularly for LS swaps. This simplifies plumbing immensely, turning a complex part of a swap into a single, manageable unit. Most other pumps reviewed are standalone units, meaning you’ll need to purchase a separate fuel pressure regulator and filter. While this adds complexity, it also offers greater flexibility in choosing components that precisely match your build’s requirements. For instance, the Holley 12-170 is a high-end standalone pump that offers PWM compatibility, allowing for advanced electronic control of fuel delivery based on engine demand, which can improve efficiency and reduce heat.

Fuel compatibility, especially with E85, is a non-negotiable for many. Most of the 255 LPH and all the 300 LPH pumps reviewed are E85 compatible, which is a significant factor for modern performance builds. Ensure your chosen pump explicitly states E85 compatibility if you plan to run it, as ethanol can be corrosive to non-compatible components.

Finally, consider the included fittings and hardware. Some pumps like the A-Premium and BREADEEP kits include a generous assortment of clamps, wiring, and AN adapters, which can save you time and money during installation. Others, like the Holley 12-927, come with basic barbed fittings. Matching your pump’s inlet/outlet to your fuel lines is critical for a leak-free and efficient system. Always ensure you have the correct fittings and tools for a safe and reliable installation.

Final Verdict

Choosing the best inline fuel pump for your EFI application really boils down to your horsepower goals, budget, and specific project needs. After reviewing these ten excellent options, here’s my take:

• For LS Swaps or fixed 58 PSI returnless systems: The GSL392 Inline Fuel Pump & 58 PSI Fuel Filter Regulator Kit is an absolute no-brainer. Its all-in-one design simplifies a often-complicated part of the build, offering fantastic convenience and reliable 58 PSI output.
• For moderate EFI upgrades (up to ~500 HP) on a budget: The Trexflow TF 2225 or the Holley 12-927 are strong contenders. They offer reliable performance for their respective horsepower ranges without breaking the bank, particularly for TBI or less aggressive multi-port EFI.
• For the sweet spot of performance (up to ~650 HP) with E85 compatibility: The 255 LPH (GSL392 type) pumps like the High Flow Pressure External Inline 255LPH from A-Premium or YOMIRACING are excellent choices. They provide a proven balance of flow, durability, and fuel compatibility, often coming with useful installation hardware.
• For serious high-horsepower builds (700+ HP) with E85 and advanced control: The Holley 12-170 is the premium pick, with its high 100 GPH flow, roller vane design, and PWM compatibility. If you need that top-tier performance and features, it’s worth the investment.
• For high-horsepower E85 builds where value and high flow are key: The EVIL ENERGY External Inline Fuel Pump 300LPH and BREADEEP Universal External Inline Fuel Pump 300LPH stand out. They offer massive flow rates, E85 compatibility, and often include a great selection of fittings, giving you a lot of performance for your dollar.

Ultimately, invest in a quality inline fuel pump for your EFI applications that meets or exceeds your engine’s fuel demands. Don’t skimp here; it’s the lifeline of your engine. Pair it with a good regulator and filter, and you’ll enjoy reliable performance for miles to come.

Comprehensive FAQ Section

Q1: Why do I need an inline fuel pump for EFI applications?
A1: Inline fuel pumps for EFI applications are crucial because EFI systems require significantly higher fuel pressure (typically 40-70 PSI) and consistent flow compared to older carbureted systems. Inline pumps are designed to operate under these higher pressures and deliver a steady supply of fuel to the injectors, ensuring proper atomization and combustion for optimal engine performance and efficiency. They are often used as standalone pumps for external mounting or as booster pumps in more complex fuel systems.

Q2: Can I use a carbureted fuel pump for my EFI system?
A2: No, you absolutely should not. Carbureted fuel pumps typically operate at much lower pressures (around 4-7 PSI) and are not designed to withstand the sustained high pressures required by EFI systems. Using a carbureted pump will result in insufficient fuel pressure, leading to lean conditions, poor performance, and potential engine damage. Always choose a fuel pump specifically designed for EFI applications.

Q3: How do I calculate what LPH/GPH fuel pump I need for my EFI engine?
A3: A common rule of thumb is to take your target horsepower, divide it by a factor (usually 0.5 for gasoline, 0.65 for E85, and 0.7 for diesel), and then add a 15-20% safety margin. For example, a 500 HP gasoline engine might need (500 HP / 0.5) = 1000 lbs/hr fuel. To convert to GPH, divide by fuel specific gravity (approx. 6.2 for gasoline) which is ~161 GPH. Adding a safety margin, you’d look for a pump around 180-200 GPH (or ~680-750 LPH). However, always consult with your tuner or engine builder, as specifics like fuel pressure, injector size, and engine efficiency can greatly impact the required pump size.

Q4: What’s the difference between a “return” and “returnless” EFI fuel system?
A4: In a return-style EFI system, fuel is pumped from the tank to the engine, through a fuel pressure regulator, and then excess fuel is returned to the tank. This maintains consistent pressure at the fuel rail. A returnless EFI system uses a pressure regulator either in the fuel tank or at the pump itself, and only sends the needed amount of fuel to the engine, with no return line from the rail. Returnless systems often simplify plumbing but can sometimes experience fuel heating issues at the rail under heavy load. Many LS swaps utilize a returnless system with an integrated filter/regulator like the GSL392 kit.

Q5: What other components do I need when installing an inline fuel pump for EFI?
A5: Beyond the pump itself, you’ll typically need: a fuel pressure regulator (unless integrated with the pump/filter), a fuel filter (10-micron recommended for EFI), appropriate fuel lines and fittings (often AN fittings are preferred for their reliability), and possibly a fuel pump relay and wiring harness to ensure proper power delivery to the pump. A check valve is also often recommended to maintain fuel pressure when the pump is off, aiding in easier starts.

Q6: Where should I mount my external inline fuel pump for EFI?
A6: External inline fuel pumps for EFI applications should ideally be mounted as close to the fuel tank as possible and, if practical, slightly below the tank’s lowest point. This allows fuel to gravity-feed into the pump, minimizing the risk of cavitation (vapor lock) and extending pump life. They should also be securely mounted on a sturdy bracket, often with a rubber isolator, to reduce noise and vibration. Protecting the pump from road debris and heat is also important.

Q7: Can I use an inline pump inside my fuel tank?
A7: No, an inline fuel pump is designed for external mounting outside the fuel tank. In-tank fuel pumps (submersible pumps) are specifically designed to operate while fully submerged in fuel, which helps with cooling and quieter operation. Trying to use an external inline pump inside a tank can lead to overheating, premature failure, and potentially dangerous conditions due to incompatible materials and lack of proper sealing.

Q8: How often should I replace my inline fuel pump?
A8: The lifespan of an inline fuel pump for EFI applications can vary greatly depending on its quality, how often the vehicle is driven, the quality of fuel used, and proper installation. Generally, a good quality pump should last 5-10 years or 100,000-150,000 miles. However, if you notice symptoms like rough idling, hesitation under acceleration, decreased fuel economy, or a whining noise from the pump, it may be time for a replacement. Always ensure your fuel filter is clean, as a clogged filter can put undue strain on the pump.