6.0L Power Stroke Blue Spring Mod

6.0L Power Stroke Fuel Regulator Blue Spring Upgrade

The blue spring fuel regulator upgrade or "blue spring mod" is an OEM recommended upgrade from Ford Motor Company. The name of the upgrade is derived from the fact that the stiffer fuel regulator spring is blue in color. This upgrade is highly recommended because it reduces the chances of injector failure resulting from low fuel pressure. A low pressure condition may cause an injector to starve for fuel, wearing and/or damaging the injector and inevitably reducing its service life. This upgrade consists of a stiffer fuel regulator spring and results in an approximate 10% fuel pressure increase.

Applicable Model Years: 2003 - 2007 6.0L Power Stroke diesel
Blue Spring Fuel Pressure Regulator Kit: Ford 6E7Z-9C165-B, International 1854267C94
6.0L Power Stroke Fuel Filter Set: Motorcraft FD-4616


A minimum 45 psi of fuel pressure is necessary at all times (including WOT) to maximize engine performance and ensure proper injection operation. Fuel pressure can be measured via a test port on the fuel filter housing (details below).

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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