7.3L Diesel Fuel Rail Crossover™ (FRx) 99-03 Powerstroke
"The Prescription For Your Fuel System Needs®"
Our 2nd Generation FRx™ System utilizes Eaton Aeroquip® 304 Stainless Steel Braided lines covered with a groundbreaking protective layer of HYTREL® from DuPont.
The FRx™ was made to solve the 'deadhead' fuel rail issue on the 99-03 Powerstroke engine by connecting the two heads and allowing a metered return you allow the air another return path, rather than forcing it through your injectors. This product was designed to eliminate the need to cut your return line and use compression fittings, so that it is a true bolt on system. We have also machined the FRx™ block to provide from stock to 72 psi of fuel pressure depending on which spring you choose to install it with. By using our kit and eliminating the air in the fuel system you can experience smoother, quieter idle, less cackle, and better throttle response among other things. You will also be increasing your injector life as well by utilizing the FRx™ and creating a regulated return back to the tank. Protective covers are also pre-installed to prevent chaffing of engine components from the SS braided line. These covers are also great if you want to keep the system looking OE and not draw attention to it once installed.
Included: Techical Info:
- FRx™ System - Exceeds SAE 100R14A
- 3 Springs for adjusting Fuel Pressure - Rated for commercially produced B100
- Viton O-ring - Temperature Rated -100˚F to +450˚F
- Parker® Fuel Sleeve - Max. Working Pressure 3000 psi
- 2 Stainless mounting bolts - Minimum Burst Pressure 12000 psi
- Custom 9/32" socket
Fuel pressure spring settings
55-60 psi silver spring
61-65 psi gold spring *Recommended
66-72 psi black spring
Riffraff Diesel Performance is committed to 100% Made in the USA. All materials are from USA resources. Every machining step is performed in the USA. Every component is assembled in the USA.
409 Reviews Hide Reviews Show Reviews
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Mandatory 7.3 mod
Injectors sound a lot quieter, and my 120hp tune is usable now. Truck used to run out of fuel after 2,500rpm but now it pulls hard throughout the whole rpm range. 10/10 would buy again.
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Improved fuel flow
I noticed an immediate improvement in fuel pressure and engine response after installing it. Very good quality and easy to install. Worth every penny.
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FRX Kit
Straight forward install, and even my wife noticed how much quieter the truck is now. Quality kit, and I have no idea why Ford didn't just do this from the start.
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FXR
Easy to install, great quality and quieted the truck down a bit!
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Installed 6/17/2025
old fittings were difficult and I installed heat shields on both hoses , truck runs better and seems to have quicker acceleration and is definitely quieter, I also replaced the exhaust back flow sensor as it had 174000 miles on it and the hesitation and abrupt change to idle disappeared.
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FRx
Love the product now that it's in. However, installation warning - the plug on the driver's side back is the easy one
The passenger side front - take your AC compressor loose first. There's exactly enough room to give you the hope that you can get the fitting in there - you can't.
Getting the fuel block installed is a trick, at least the springs are magnetic when you drop em behind the alternator. The gasket isn't. Took a while to find that one.
I'll let you know on improvement, had to do a new turbo after getting this and the HPx installed.... :/ -
Frx
Easy install stall and noticeable improvement in idle noise as well as throttle response. It gives you the feeling your truck has been misfiring this whole time and now it’s fixed.
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Fuel Crossover rail
Have been using Riff Raff products for over 20 years, great dependable service and products. The fuel Crossover rail is a great addition to my modifications for my 02 F350 Powerstroke, wish this would have been around years ago, easy install, follow the directions, smooth acceleration, very quiet in cab, feels like it complimented the other modifications with some more hintable hp, will need to see if there is any fuel mileage gains in the near future, but I am more for smiles than miles
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FRX
Good folks at Riff Raff
Both 1/8 NPT adaptors required thread chasing as both would NOT thread into the fuel rail.
The thread simply would not catch!
This required taking a 1/8 npt die and running threads further there by having a taper on the adapter.
Easy fix but a bit annoying.
Thanks
