How to Check the Fuel Pressure on an Expeditionby Allen Moore
Ford Expeditions are fuel injected vehicles requiring a constant fuel pressure that fluctuates with the throttle position. If the fuel pressure is too high or too low, it can cause drivability issues that are detrimental to your Expedition’s engine and emissions systems, as well as your wallet. With that in mind, if you suspect your Expedition has fuel pressure problems, you should have it checked out immediately and repair the problem as soon as possible.
Raise the hood, put your safety glasses on and locate the fuel system test port, located in the fuel rail. Unscrew the cap on the port by hand and set it aside where you won’t lose it.
Connect the fuel pressure gauge to the port and maneuver the fuel pressure gauge under the hood near the cowl and up onto the windshield so you can lay it facing into the cab of the Expedition. Secure it in place by putting it between the windshield and the wiper blade.
Get in the driver seat of the Expedition and turn the ignition key to the run position, (one notch prior to actually cranking the engine over). The needle on the fuel pressure gauge should rise to approximately 32 to 45 PSI, depending on the year and engine of your Expedition. Watch the needle to make sure the pressure doesn’t drop off.
Shut the engine off and see if the pressure changes. It should remain constant, even after the key is turned off. This constant pressure keeps fuel in the injectors for quick start up. Start the engine again and tap the throttle; the needle should quickly rise roughly 5 PSI, then return to normal when the engine slows back down to idle.
Disconnect the fuel gauge from the fuel test port and reinstall the cap on the port to prevent dirt or other contaminants from entering the port and potentially causing a fuel leak.
- If the pressure fails to rise to the acceptable PSI range, or it falls quickly after turning the key off, you have a fuel pressure concern that should be diagnosed and repaired as soon as possible.
- Never work on a fuel system while smoking or near open flames.
- It is best to have fuel system diagnosis performed by a certified technician, due to the inherent dangers of a malfunctioning fuel system.