Product Description
2002-2005 Honda Civic Si EP3 Complete PTFE Fuel System (Level 4)
The JBtuned Level 4 Complete Fuel System replaces the factory fuel-delivery plumbing on the 2002-2005 Honda Civic Si EP3 with a complete aftermarket tank-to-engine-and-back feed-and-return system.
The original chassis fuel feed is replaced with JBtuned 350 Series PTFE fuel hose, and a dedicated 6AN return is added from the engine bay back to the fuel tank.
Choose a 6AN or 8AN main fuel feed based on the requirements of the build. The return remains 6AN with either configuration.
This is Level 4 in the JBtuned EP3 fuel-system lineup: “I want to replace everything.”
Level 4 at a Glance
- Fitment: 2002-2005 Honda Civic Si EP3
- System Type: Complete tank-to-engine-and-back aftermarket feed-and-return fuel system
- Factory Chassis Fuel Feed: Replaced
- Dedicated Fuel Return: Added
- Feed Line: 6AN or 8AN
- Return Line: 6AN
- Fuel Hose: JBtuned 350 Series PTFE
- Fuel Compatibility: Pump gasoline, E85 / ethanol and compatible race fuels
- Fuel Filter: Inline fuel filter included
- Fuel Rail: Compatible aftermarket K-Series fuel rail required
- Fuel Pressure Regulator: Compatible external adjustable regulator required
- Flex-Fuel Sensor Provision: Optional plumbing configuration
- Ethanol-Content Sensor: Not included
- Fuel Pump: Not included unless purchased separately
- Fuel Pump Hanger Upgrade: Optional and available only with this Complete Fuel System
- Under-Car Brackets: Optional for 8AN feed / 6AN return with JBtuned 350 Series PTFE only
What Comes With the Base Level 4 System
- Complete JBtuned 350 Series PTFE fuel-feed plumbing from the fuel tank to the engine bay in the selected 6AN or 8AN size
- Complete JBtuned 350 Series PTFE 6AN return plumbing from the engine bay back to the fuel tank
- Pre-assembled fuel-line assemblies configured for the selected engine and fuel-system options
- Inline fuel filter
- Fuel-rail connection components for the selected configuration
- Fuel-pressure-regulator connection components for the selected configuration
- Required AN connection hardware for the configured base fuel system
Exact line and connection configurations vary depending on the engine, intake manifold, feed-line size, fuel rail, regulator, hanger and selected options.
The base system does not include the fuel rail, fuel pressure regulator, fuel pump, Fuel Pump Hanger Upgrade Kit, ethanol-content sensor or under-car Fuel & Brake Line Holder Brackets unless specifically selected or purchased separately.
Required Parts Not Included
Aftermarket K-Series Fuel Rail: A compatible aftermarket K-Series fuel rail is required. Select the fuel rail installed on the engine when ordering so JBtuned can configure the appropriate fuel-system connections.
External Fuel Pressure Regulator: A compatible external adjustable fuel pressure regulator is required for the dedicated return-style system.
Select the appropriate regulator inlet configuration when ordering so JBtuned can supply the correct regulator-side connection.
Fuel Pump: Fuel-pump requirements depend on the engine combination, fuel being used, injector demand, operating pressure and expected fuel demand. The fuel pump is not included with the base system.
What Level 4 Changes
The factory EP3 fuel system uses a different architecture than earlier Honda chassis with separate factory feed and return lines.
The JBtuned Level 4 system replaces the original chassis fuel feed with a dedicated aftermarket AN feed and adds a dedicated 6AN return from the engine bay back to the fuel tank.
This creates a complete aftermarket tank-to-engine-and-back return-style fuel-system architecture.
Feed-line size, fuel type and ethanol-content-sensor integration are configuration choices within Level 4 rather than separate fuel-system levels.
6AN or 8AN Feed With 6AN Return
The EP3 Level 4 system is available with either a 6AN or 8AN main fuel feed.
- 6AN Feed / 6AN Return
- 8AN Feed / 6AN Return
The return remains 6AN with either feed configuration.
Fuel-pump capability, injector demand, fuel type, operating pressure and expected fuel demand should all be considered when selecting feed-line size.
A larger fuel line does not by itself increase the output capability of the fuel pump or the rest of the fuel system.
350 Series PTFE - Pump Gas / E85 / Compatible Race Fuels
The EP3 Level 4 system uses JBtuned 350 Series PTFE fuel hose for both the feed and return plumbing.
350 Series PTFE is appropriate for:
- Conventional pump gasoline
- E85 and ethanol-based fuels
- Compatible race fuels
- Gasoline builds that may move to ethanol-based fuel later
Choosing this system does not mean the vehicle has to run E85.
The PTFE plumbing provides broader long-term fuel compatibility whether the vehicle runs conventional pump gasoline, E85 or another compatible fuel.
E85 Compatibility Is Not the Same as Flex-Fuel Sensor Integration
JBtuned 350 Series PTFE makes the fuel plumbing suitable for pump gasoline, E85 and other compatible fuels.
That does not by itself make the vehicle a sensor-based flex-fuel system.
An ethanol-content sensor can provide real-time fuel-composition information to a compatible ECU for a sensor-based flex-fuel strategy. Sensor wiring, engine-management compatibility, ECU configuration and tuning are separate from the fuel-system plumbing.
If you want the fuel-system plumbing prepared for a compatible ethanol-content sensor, select the Flex-Fuel Sensor Provision when ordering.
The ethanol-content sensor itself is not included with this option.
Not sure which configuration you need? Read our guide to E85, PTFE fuel lines and flex-fuel systems.
Aftermarket K-Series Fuel Rail Required
The EP3 Level 4 system requires a compatible aftermarket K-Series fuel rail.
Select the fuel rail installed on the engine when ordering so JBtuned can configure the appropriate connection.
Different aftermarket fuel rails use different connection arrangements. If your fuel rail is not represented in the available options, contact JBtuned before ordering.
External Fuel Pressure Regulator Required
This complete return-style fuel system requires a compatible external adjustable fuel pressure regulator.
The regulator controls fuel pressure and provides the regulated return path back to the fuel tank.
Select the appropriate regulator inlet configuration when ordering so JBtuned can provide the correct regulator-side connection.
The fuel pressure regulator shown in the product photos is an example installation and is not included with the base fuel system.
Regulator placement and fuel-line routing vary depending on the fuel rail, intake manifold, engine configuration and surrounding components.
If you are unsure whether your fuel rail and regulator combination is compatible, contact JBtuned before ordering.
Inline Fuel Filter Included
The EP3 Level 4 Complete Fuel System includes an inline fuel filter as part of the base fuel-system package.
The filter is incorporated into the configured fuel system so the feed, filtration and return plumbing work together as a complete package rather than requiring the customer to determine the fuel-line and filtration connections separately.
Optional Flex-Fuel Sensor Provision
The Flex-Fuel Sensor Provision configures the fuel-system plumbing around the installation of a compatible ethanol-content sensor.
This option prepares the plumbing for sensor installation. It does not include the ethanol-content sensor, sensor wiring, controller, ECU input or tuning required to use the sensor signal.
If the vehicle will run E85 without a sensor-based flex-fuel strategy, the 350 Series PTFE fuel system is still compatible with E85. The sensor provision is specifically for customers who want the plumbing arranged around ethanol-content-sensor installation.
JBtuned offers the Genuine Continental Flex-Fuel Sensor for compatible installations.
Compatible Flex-Fuel Sensor Quick-Disconnect Fittings are also available individually. A typical compatible sensor installation uses two fittings.
Fuel Pump Hanger Upgrade Kit
A complete aftermarket feed-and-return system requires appropriate feed and return connections at the fuel tank.
For customers who need a solution for the factory EP3 fuel-pump hanger, JBtuned offers a Fuel Pump Hanger Upgrade Kit as an option with this Complete Fuel System.
The EP3 Fuel Pump Hanger Upgrade Kit is available only when purchasing this complete fuel-system kit and is not sold by JBtuned as a separate standalone product.
The factory EP3 hanger requires substantial modification to accommodate the larger aftermarket feed-and-return connections. This is considerably more involved than installing a simple bolt-on fitting.
JBtuned provides a detailed installation guide covering the hanger modification:
View the RSX / EP3 Fuel Pump Hanger Modification Installation Guide
Review the installation guide before selecting the hanger option so you understand the modification required.
The hanger configuration also depends on the fuel pump being used, so select the appropriate fuel-pump configuration when ordering.
If the vehicle already has a properly configured aftermarket or modified hanger that provides the required feed and return connections, the JBtuned hanger upgrade may not be necessary.
The modified fuel-pump hanger shown in the product photos is an installation example and is not included unless the Fuel Pump Hanger Upgrade Kit option is selected.
Need a Fuel Pump?
Fuel-pump requirements depend on the engine combination, fuel being used, injector demand, operating pressure and expected fuel demand.
If you need a fuel pump, shop JBtuned fuel pumps.
Under-Car Fuel & Brake Line Brackets
For a clean and secure underbody installation, JBtuned offers the JBtuned RSX DC5 / EP3 Civic Si Fuel & Brake Line Holder Brackets.
These chassis-specific brackets use the factory underbody mounting studs and organize the aftermarket fuel lines alongside the vehicle's brake and EVAP/emissions lines.
The current JBtuned RSX / EP3 bracket configuration is designed specifically for the 8AN feed / 6AN return version of this system using JBtuned 350 Series PTFE hose.
The bracket kit is not currently designed for the 6AN feed / 6AN return configuration.
The brackets also include a dedicated position for the factory underbody EVAP/emissions line when that line is retained.
EVAP / Emissions System Considerations
The JBtuned RSX / EP3 under-car bracket system allows the factory underbody EVAP/emissions line to remain in place.
Depending on the complete fuel-system configuration, other EVAP-related components may still need to be removed or reconfigured to provide appropriate space for the fuel filter, optional ethanol-content sensor or other fuel-system components.
Inspect the EVAP system and planned component locations before completing the installation.
Designed Around Modified EP3 Applications
The EP3 Level 4 system can be configured around the engine, intake manifold, fuel rail and other components installed on the vehicle.
Final routing can vary based on engine configuration, intake manifold, engine mounts, power-steering configuration, accessory layout, header, turbo system and surrounding engine-bay components.
Fuel lines should be kept as far away as practical from exhaust manifolds, turbochargers, downpipes and other high-temperature components.
Turbocharged and other high-heat configurations may require additional thermal protection when adequate separation cannot be maintained.
Retain factory firewall and underhood heat shielding wherever practical.
Vehicle Fitment
- 2002-2005 Honda Civic Si EP3
This system is intended for modified EP3 applications using a compatible aftermarket K-Series fuel rail and external adjustable fuel pressure regulator.
Final fitment and routing depend on the engine, intake manifold, fuel rail, regulator, accessory configuration, engine mounts, exhaust or turbo system and other surrounding components installed on the vehicle.
If your combination is unusual or your components are not represented in the available ordering options, contact JBtuned before ordering.
Ordering Options
Engine: Select the engine configuration installed in the EP3.
Intake Manifold: Select the intake manifold being used so the fuel system can be configured around the engine-bay components installed on the vehicle.
Fuel Rail: Select the compatible aftermarket K-Series fuel rail installed on the engine. Different rails require different connection configurations.
Feed Line Size: Choose either a 6AN or 8AN main fuel feed. The dedicated return remains 6AN.
Regulator Inlet Size: Select the inlet configuration used by the external adjustable fuel pressure regulator so JBtuned can supply the appropriate connection.
Fuel Pump Hanger Upgrade Kit: Select this option if the factory EP3 hanger needs to be modified for the complete aftermarket feed-and-return system. This upgrade is available only with the complete fuel-system purchase and is not sold separately. Review the hanger modification guide before ordering.
Flex-Fuel Sensor Provision: Select this option if you want the fuel-system plumbing configured for compatible ethanol-content-sensor integration. The sensor itself is not included.
Under-Car Fuel Line Brackets: Add the JBtuned RSX DC5 / EP3 Civic Si Fuel & Brake Line Holder Brackets when using the compatible 8AN feed / 6AN return JBtuned 350 Series PTFE configuration.
JBtuned EP3 Fuel-System Levels
- Level 1 - “I Just Need the Feed Line”: Retains the factory chassis fuel supply and factory in-tank filter arrangement while replacing the engine-bay feed with 6AN JBtuned 350 Series PTFE plumbing to a compatible aftermarket K-Series fuel rail.
- Level 4 - “I Want to Replace Everything”: Replaces the original chassis fuel feed and adds a dedicated aftermarket return to create a complete tank-to-engine-and-back feed-and-return system. You are here.
Which EP3 Fuel System Should I Choose?
Choose Level 1 if you want to upgrade the engine-bay fuel feed while continuing to use the factory chassis fuel supply and in-tank filter arrangement.
Choose Level 4 if you want to replace the original chassis fuel feed and convert the vehicle to a complete aftermarket feed-and-return system from the fuel tank to the engine and back.
Also Available for the Acura RSX DC5
For 2002-2006 Acura RSX DC5 applications, see the JBtuned RSX DC5 Complete PTFE Fuel System.
Installation Notes
- This is a complete aftermarket fuel-system installation from the fuel tank to the engine bay and back.
- The original chassis fuel feed is replaced and a dedicated 6AN aftermarket return is added.
- Installation requirements vary depending on the engine, intake manifold, fuel rail, fuel pressure regulator, fuel pump, hanger configuration, accessory configuration, turbo setup and optional ethanol-content-sensor equipment.
- All fuel lines must be securely mounted and routed away from exhaust heat, sharp edges, belts, pulleys, moving components and areas where road debris or abrasion may damage the hose.
- Verify clearance around the fuel rail, engine mounts, power-steering components, transmission area, firewall, heat shielding and surrounding engine-bay components before finalizing line routing.
- Customers selecting the Fuel Pump Hanger Upgrade Kit should review the installation guide before beginning installation. The hanger modification is substantially more involved than a simple bolt-on adapter.
- Turbocharged and other high-heat applications require additional attention to fuel-line clearance and thermal protection.
- After installation, pressurize the fuel system and carefully inspect every connection for leaks before starting or operating the vehicle.
Changes to injectors, fuel pressure, fuel pump, fuel type, ethanol-content-sensor integration or other engine components may require appropriate ECU configuration and tuning.
Professional installation and tuning are recommended where applicable.
For off-road use only.
Questions About Your EP3 Fuel System?
If you are unsure which configuration is appropriate for your build, contact JBtuned with your vehicle year, engine, intake manifold, fuel rail, fuel pressure regulator, fuel pump, fuel being used, approximate power goals and whether you plan to use an ethanol-content sensor.
