Ford 6.0 Upgraded Fuel Pressure Spring Kit
This is a replacement upgraded fuel pressure spring (blue spring) that will raise the stock fuel pressure about 18-20psi. Ford used a weaker fuel pressure spring when building the 6.0L trucks. Most trucks with a factory spring will only have around 40psi of fuel pressure at part throttle on stock tuning. They have about 45psi when idling. The 6.0 needs at least 45psi to properly fire the injectors. Ford released an updated fuel pressure spring kit, which will increase fuel pressure to around 65psi at idle and 58psi at WOT.
Remove the air cleaner, loosen up the CAC tube and move it out of the way. Loosen and then remove the fuel line on the fuel pressure regulator cover. Loosen the 4 T27 Torx screws on the same cover. Keep pressure on the cover because the spring will pressure will push it off. The cover will come off, along with the spring and the poppet valve. Slide the spring out of the poppet valve. Slide the new spring back on. Reinstall the cover.
Removing the upper radiator hose makes the job much easier, but not necessary.