Looking to convert your Jeep's OBD2 return-less fuel system to a return style system? The BWE Billet Fuel Pump Module kit allows for a painless conversion, as well as upgrading to a higher flow fuel pump along with E85 compatibility (pump and OEM sump not included).
- Why switch to a return style fuel system?
- Adjustable Fuel Pressure: The Jeep's factory OBD2 fuel system uses a fixed pressure regulator that is mounted permanently to the fuel module cap at the tank. The pressure is factory set at about 49psi. While this works perfectly fine for a completely stock engine setup, it is not ideal for engine swaps that require higher base pressures (LS swaps for example) or forced induction setups. Converting to a return style system allows for an inline external regulator to be used (not included). Not only does this allow you to adjust your base fuel pressure, but it allows for a vacuum/boost port reference.
- The Forced Induction Problem: Converting to return style systems for forced induction applications is nothing new. The inherent problem stems from the pressure differential that is created between the fuel injector inlet and outlet when under boost. The diagram below (courtesy of Haltech USA) shows this problem in detail. Essentially with a base pressure of 45lbs and 10lbs of boost being put through the engine, the effective fuel pressure at the injector is only 35lbs! This can cause inconsistent tuning and drastically decreases the total amount of fuel the injector can flow. If you would like to know more we recommend watching the great video done by Haltech here: https://youtu.be/aWuFFhKuQZs
- Vapor Lock: A common problem with the Jeep's fuel system is caused by the fact that the fuel rail is directly above the hot exhaust manifold. This heat can become so extreme at times that it leads to the fuel boiling in the fuel rail causing stalling or preventing the engine from restarting until the fuel cools back down. Jeep even addressed this with some late models being fitted with a basic heat shield around the injectors and portions of the fuel rail. While heat shielding does do a great job at lessening the amount of heat soak, converting to a return style system prevents the fuel from boiling in the rail completely by flowing excess fuel through the rail and back to the tank.
- The Design: The Billet aluminum module cap utilizes a bolt on stainless steel bracket that allows the retention of the OEM aluminum sump. This is important because the sump not only is the mount for the fuel level sender, but also incorporates a check valve to prevent fuel starvation even with a low tank of fuel. The valve also keeps the fuel pump surrounded with fuel which helps keep the fuel pump cool thus extending it's service life.
The OEM design utilizes a small clip that holds the fuel pump in place. Because of this our kit is designed around the AEM PN: 50-1220 E85 compatible 320lph fuel pump. There may be other pumps on the market that work, but this AEM unit is the exact same dimensions as the OEM unit.
- What's required (not included in the kit):
- OEM Fuel Pump Module: The kit will also work with many of the aftermarket
replacement modules: Just make sure it has the aluminum sump!
- Fuel Pump: We highly recommend the AEM 340lph (PN: 50-1220) as it has the same
dimensions as the factory unit. They are also amazingly quiet!
- New inner and outer pump strainers: Airtex PN's: FS221 and FS220 (or similar)
- Fuel Rail/External Pressure Regulator: While an OBD1 fuel rail/regulator could be used,
we highly recommend using a NRT Billet aluminum fuel rail or welding a 6AN steel fitting
to the end of your fuel rail for the return line. An external 1:1 rising rate pressure
regulator is also highly recommend especially for boosted applications. http://www.nrtautosports.com/product/97-01-jeep-4-0-billet-aluminum-performance-fuel-rail
- 6AN feed and return lines: If you're intending on using E85 make sure that you use
ethanol compatible lines. Adding an inline fuel filter is a great addition as well but not
required.
Click the link below for a copy of the installation instructions:
