The DieselSite Fuel Tank Sending Unit is a direct-replacement in-tank fuel sender and pickup module engineered specifically for 1999–2007 Ford Super Duty F-250 and F-350 trucks equipped with the 7.3L or 6.0L Powerstroke diesel engine. Built to restore precise fuel gauge readings and clean fuel pickup without requiring custom lines or tank modifications, this unit serves as a direct OE-style replacement on 6.0L applications while functioning as a must-have upgrade on late 1999–2003 7.3L trucks by eliminating the problematic factory in-tank filter socks and mixing chamber that cause fuel restriction and aeration.

Quick Specs & Kit Inclusions

• Application: In-tank fuel level sending unit and suction/return module
• Configuration Options: Model-specific versions for Short Bed (FSUSB), Long Bed (FSULB), and 2000–2005 Excursion rear tanks
• Plumbing Interface: Factory quick-connect male tube ports for 100% plug-and-play connection to factory fuel lines
• Level Sensor: Integrated OE-spec electronic rheostat sender card and calibrated float arm
• 7.3L Upgrade Benefit: Eliminates the OEM in-tank fine mesh filter socks and mixing chamber (ideal for trucks running pre-pump filters or aftermarket fuel systems)
• Emissions Status: 50-state legal (direct mechanical replacement)
• Direct Interchange Part Numbers: Ford F81Z-9275-CA, F81Z-9275-AJ, 6C3Z-9275-EA, 5C3Z-9275-BA, 6C3Z-9275-BA, 6C3Z-9275-VA, DieselSite FSUSB, FSULB
• What's in the Box: (1) DieselSite Fuel Tank Sending Unit Assembly with Pre-Calibrated Float Arm and (1) Tank Flange Sealing Gasket

Problem Solved: Curing Inaccurate Fuel Gauges & 1/4-Tank Fuel Starvation

Two primary failure modes plague the factory fuel sending units on 1999–2007 Powerstroke trucks. First, the delicate electronic resistance wiper tracks on the OEM level sender wear through, corrode, or get fouled with fuel varnish, causing erratic fuel gauge spikes, stuck needles, or dead empty readings. Second, on 7.3L models, the factory mixing chamber and in-tank filter socks clog with asphaltites, algae, and debris, starving the frame-mounted pump. When the fragile plastic "duckbill" pickup foot cracks or breaks off, the pickup tube ingests air around the 1/4-tank mark. This air intrusion causes severe HEUI injector cavitation, loud engine cackle, loss of power, and premature injector failure. The DieselSite sending unit delivers an accurate fuel level reading and a reliable, open-suction pickup design that restores proper fuel supply to the lift pump.

Fitment

• 1999–2003 Ford F-250 Super Duty 7.3L Powerstroke Turbo Diesel
• 1999–2003 Ford F-350 Super Duty 7.3L Powerstroke Turbo Diesel
• 2003–2007 Ford F-250 Super Duty 6.0L Powerstroke Turbo Diesel
• 2003–2007 Ford F-350 Super Duty 6.0L Powerstroke Turbo Diesel
• 2000–2005 Ford Excursion 7.3L & 6.0L Powerstroke Turbo Diesel (requires Excursion-specific rear-tank configuration)
• Important Fitment Notes:
  • Verify bed length prior to ordering: Short Bed (approx. 29-gal) and Long Bed (approx. 38-gal) units use different suction tube lengths and float arms and are not interchangeable.
  • Does not fit 1994–1997 "OBS" Ford trucks.
  • Does not fit Cab & Chassis aft-axle tanks or Econoline E-Series vans.
  • On 7.3L trucks, eliminating the in-tank filter socks requires using an external pre-pump fuel filter (such as a Dahl-like pre-filter or aftermarket lift pump system) to protect the electric frame pump from coarse tank sediment.

Safety & Tank Access: Run fuel down as low as possible before starting. Access the top of the fuel tank by either lowering the tank using a transmission jack after unbolting the two support straps, or by unbolting the truck bed (six or eight T50/T55 Torx bolts) and shifting/sliding the bed backward 2 to 3 feet to expose the top module. Factory Unit Disconnection: Disconnect the electrical wiring harness connector. Using 5/16" and 3/8" fuel line disconnect tools, release the factory push-lock supply and return quick-connect fittings. Blow away all loose road dirt, sand, and debris from around the retaining ring flange using compressed air. Lock Ring & Unit Removal: Rotate the metal tank lock ring counter-clockwise using a fuel tank lock ring tool or a brass drift punch and mallet. Carefully lift the old sending unit up and maneuver the float arm out through the tank neck opening. Discard the old rubber flange gasket. Tank Floor Inspection & Cleanout: Shine an inspection light into the tank. Siphon out any settled sediment, slime, microbial growth, or broken pieces of the original factory plastic pickup foot before installing the new unit. Gasket & Unit Positioning: Place the supplied new sealing gasket into the machined groove of the tank neck flange. Carefully lower the DieselSite sending unit into the tank, guiding the float arm gently into place so it does not bend against internal tank baffles. Orientation & Lock Ring Installation: Align the top plate locating notch with the tab on the tank neck to ensure the tube ports face the original factory fuel line routing direction. Reinstall the metal lock ring and rotate it clockwise until fully engaged against the positive mechanical stops. Line & Harness Reconnection: Reconnect the factory push-lock quick-connect fuel lines onto the supply and return tube nipples until they click securely into place. Reconnect the electrical harness plug until the locking tab snaps shut. Priming & Verification: Add at least 5 gallons of fresh diesel fuel. Turn the ignition key to the "RUN" position (KOEO) for 30 seconds without cranking the engine to cycle the electric lift pump and purge air from the lines. Verify that the dashboard fuel gauge reads accurately and reflects the added fuel. Start the truck and inspect the top flange and quick-connect fittings for zero leaks before securing the tank or truck bed.