6.0 Power Stroke Fuel Pressure Regulator Spring Replacement

Applicable Models:

2003 - 2007 Ford F-250, F-350, F-450, F-550 Super Duty
2003 - 2005 Ford Excursion
2004 - 2010 Ford Econoline E-350
2003 - 2008 Ford F-650, F-750 medium duty trucks

Applicable Engine(s):

6.0 Power Stroke V-8

6.0 Power Stroke Fuel Pressure Regulator Operation

The 6.0L Power Stroke's fuel system is quite simple and reminiscent of that employed by the previous generation 7.3L Power Stroke diesel. An electric fuel pump draws fuel from the tank and ultimately delivers it to the engine mounted fuel filter housing where it is then distributed to the left and right cylinder heads. Passages in the cylinder head supply fuel to each individual injector.

A spring and plunger assembly incorporated into the engine mounted fuel filter housing maintains a system pressure of 45 to 55 psi by bleeding off excess pressure to the fuel tank via a return line.

6.0 Power Stroke Blue Spring Upgrade

The "blue spring mod" or "blue spring upgrade" is an updated fuel pressure regulator spring released and recommended by Ford Motor Company; the name is derived from the fact that the updated spring is blue in color so that a technician can easily recognize that the upgraded part has been installed and it can be differentiated from the original fuel pressure regulator spring. The updated spring is slightly stiffer than the factory installed variation and may be of a more suitable material that resists deformation over time. It is said to increase fuel pressure by approximately 10%.

Rapid injector wear and even failure can result from low fuel pressure and/or fuel starvation as it allows the plunger in the injector to run dry. The low tolerances in the machining of the injector components lends them susceptible to even small dimensional changes, thus constant lubrication is necessary for a long, reliable service life.

Fuel Pressure Spec & Testing

A minimum of 45 psi of fuel pressure is necessary at all times, including wide-open-throttle and full load conditions, to maximize engine performance and ensure proper injector operation. 45 to 55 psi is a normal key on, engine off reading at the fuel filter housing. Fuel pressure is typically measured via a test port on the fuel filter housing; see testing fuel pressure on a 6.0 Power Stroke for specific procedures. Low fuel pressure indicates a restriction in the fuel system, a malfunctioning fuel pressure regulator, or a faulty fuel lift pump.

Associated Parts List


Part Number(s)


Pressure regulator spring & seal kit, w/o cover

Ford 6E7Z-9C165-B
International 1854267C94
Alliant Power AP0086


Pressure regulator spring & seal kit, w/ cover

Ford 3C3Z-9T517-AG

Fuel filter set

Motorcraft FD-4616


Fuel pressure test adapter

Shrader Adapter


Fuel pressure gauge kit

OTC 4480


[1] - Pressure regulator spring and seal kit is available with or without the pressure regulator cover; recommend kit 3C3Z-9T517-AG with pressure regulator cover.
[2] - Fuel filters should be replaced after replacing fuel pressure regulator spring; kit includes chassis and engine mounted fuel filters.
[3] - Allows fuel pressure test equipment with a common Shrader valve fitting to be connected and read fuel pressure inside of the engine mounted filter housing.
[4] - Any common fuel pressure test gauge with an appropriate measurement range will suffice; recommended product listed

How to Replace the Fuel Pressure Regulator Spring on a 6.0 Power Stroke

Click any thumbnail to view high resolution fullsize image w/ addition details (where applicable)

6.0 Power Stroke fuel filter housing

• Disconnect both negative battery cables.

• Remove the air filter assembly and cold-side intercooler tube to improve access to the side of the fuel filter housing.

• Remove the fuel filter cap and fuel filter element. Completely drain the fuel filter housing with a turkey baster, syringe, or similar means.

6.0 Power Stroke fuel pressure regulator location

• Remove the fuel pressure regulator cover using a T-27 Torx driver (4 bolts). Maintain light pressure against the bottom of the cover as the spring tension will have a tendency to push it outwards and you don't want to accidentally lose any parts. The fuel line connected to the regulator cover does not need to be removed unless it is also being replaced.

6.0 Power Stroke fuel regulator housing removal

• The lower regulator cover bolts can be difficult to access because of the position of the radiator hose. We use a short T-27 Torx bit designed to slip into a 1/4" nut driver. The bit can be inserted into the head of the bolt and rotated with a 1/4" wrench (see image for details). This eliminates the need to remove or pull on the upper radiator hose.

Blue spring mod

• Blue spring upgrade kits are provided by various manufacturers, including Ford Motor Company and International. A minimal kit will include a new spring and regulator cover gasket. More elaborate kits may include additional parts which should be removed and replaced as necessary. The kit we are installing includes the parts pictured.

Installing blue spring into fuel pressure regulator

• Carefully retrieve the spring, spring seat, and cover gasket. Play in the fuel line will allow the cover to be pulled out of the way to provide ample room.

• Install the new components in reverse order. Lightly coat the cover gasket and spring seat o-ring with clean motor oil before installing.

• Reinstall the fuel regulator cover to the fuel filter housing, being cautious not to pinch the gasket. Do no overtighten the bolts, the aluminum threads will strip easy; tighten just enough to seat the cover gasket completely.

Old fuel regulator spring removed

• Install a new fuel filter element and fuel filter cap o-ring (coat o-ring in clean motor oil before installing). Torque filter cap to 14 N-m (10 ft-lbs).

• Reconnect both negative battery cables.

• Cycle the key into the "run" position three times for at least 10 seconds per cycle (once you hear the fuel pump turn off, turn the key to "off" position and back to the "run" position). This will fill the fuel filter housing and prime the fuel system.

• Start the engine and verify that there are no leaks. You may wish to test fuel pressure, the procedures of which can be found here: 6.0L Power Stroke fuel pressure test procedures