Replace Fuel Sending Unit
Frontier: Replace Fuel Sending UnitWARNING:
^ Before performing any of the Service Procedures below, be certain there are no ignition sources (i.e., open flames, sparks, etc.) in or around the vehicle/work area.
^ Make sure the appropriate rated fire extinguisher is available for immediate use.
^ Use suitable protective gloves, safety glasses, or face shield.
CAUTION:
Use suitable covers to protect carpet, upholstery, etc.
NOTE:
The Fuel Sending Unit that you remove from the vehicle may look different from the new replacement service part (see Figure 43 above).
1. Release the fuel pressure from the fuel system using CONSULT-II (or other suitable method). Follow the procedure in the "EC" section of the Service Manual.
2. Use a suitable device to remove the fuel from the fuel tank.
3. Remove the fuel tank:
^ For detailed instructions on fuel tank removal and installation, refer to the vehicle specific Service Manual, Section FE (Fuel And Exhaust)/Fuel System/Removal and Installation/Fuel Tank.
WARNING:
Follow all warnings and cautions provided in the Service Manual. Before disassembly: use duct tape and an "indelible" marker (permanent marker), to mark the matching pipes and hoses, which are attached to the fuel filler neck (see Figure 12).
^ The hoses MUST be re-connected to the same pipes they were removed from.
^ If the hoses are re-connected incorrectly, refueling difficulties may occur.
4. Plug all Fuel Tank openings, except the Pressure Port (see Figure 13).
^ Use Kit A for Fuel Tanks with 3 ports (1999-2000 Frontier & Xterra)
^ Use Kit B for Fuel Tanks with 5 ports (2000-2003 Frontier & Xterra)
NOTE:
Kit A and Kit B will be automatically sent to each dealer.
5. Install the Connector Covers (from Kit #B5060-79900) onto the Fuel Sending Unit Connectors until they are fully seated (see Figure 13).
6. Remove the Fuel Sending Unit as follows:
a. First, use shop air to clean the area around the Fuel Sending Unit and Mounting Flange (see Figure 14).
b. Then, apply Rust Penetrant (999MPA3020P) to the Fuel Sending Unit Mounting Flange Bolts (see Figure 15). Allow the penetrant to "soak" or a few minutes.
c. Using hand tools ONLY, gently remove the Fuel Sending Unit Mounting Flange Bolts.
d. Remove the Fuel Sending Unit.
NOTE:
To disconnect the fuel return hose from the Fuel Sending Unit, do the following:
^ Push UP on the fuel return hose connector 1 to 2 mm (around 1/16-inch). See Figure 16A.
^ With the hose connector pushed UP, hold the two plastic tabs. See Figure 16B.
^ While holding the plastic tabs, pry DOWN on the hose connector with hose removal pliers (such as #47900, Lisle Corporation or equivalent). See Figure 16C.
NOTE:
The hose removal pliers (noted above) are available from TECH-MATE.
^ Cut and discard the old Fuel Sending Unit O-ring. You'll be installing a new O-ring later.
7. Inspect the Fuel Tank Sending Unit Mounting Flange and O-Ring Groove (see Figure 17 and 18).
NOTE:
If a new Fuel Tank is installed, perform steps 11 & 12 below, then proceed with step 17.
8. Insert the Protective Cover provided in Kit A (3-port) or Kit B (5-port) in the Fuel Tank opening (see Figure 19).
CAUTION:
Make sure the Protective Cover is properly inserted/seated to prevent rust and debris from entering the Fuel Tank.
9. Completely clean the Fuel Tank Sending Unit Mounting Flange and O-Ring Groove by hand using Scotch Brite Pad 3M #051131-07447 or a copper/bronze bristle brush. See Figure 20.
WARNING:
^ Do NOT use any power tools (pneumatic or electric) for cleaning the Fuel Tank Sending Unit Mounting Flange and O-Ring Groove.
^ Use proper care and precaution when working around gasoline.
^ Make sure the appropriate rated fire extinguisher is available for immediate use.
^ Use suitable protective gloves, safety glasses, or face shield.
10. Use shop air to completely blow off/clean the Fuel Tank Sending Unit Mounting Flange and O-Ring Groove.
11. Install the new Fuel Sending Unit O-ring in the groove on the fuel tank.
12. Use the new mounting screws to install the Fuel Sending Unit on the fuel tank. Refer to the "FE" section in the applicable Service Manual.
^ Tighten the Fuel Sending Unit mounting screws to 2.0 - 2.5 N-m (0.20 - 0.26 kg-m, 17.4 - 22.6 in-lb).
REMEMBER: If a new Fuel Tank is installed, perform steps 11 & 12 then proceed with step 17.
13. Now check for leaks. Put some soapy water around the outer edge of the Fuel Sending Unit Mounting Flange.
14. Connect Essential Tool Vacuum Pump J-42909 to the Fuel Tank Pressure Port (see Figure 21).
^ Before using the Vacuum Pump, make sure it works properly and can hold pressure.
15. Apply air pressure, not to exceed 2 p.s.i. (Maximum) regulated air pressure, to the Fuel Tank using the Vacuum Pump/supply air.
NOTE:
After you pressurize the Fuel Tank, "pinch off" the hose going to the supply air to prevent pressure leakage.
16. Monitor the air pressure in the Fuel Tank for 1 minute:
a. If the air pressure holds at 2 p.s.i. (for 1 minute), and there are no bubbles around the Fuel Sending Unit, proceed with the next step.
b. If the air pressure does NOT hold at 2 p.s.i. (for 1 minute), and/or there are bubbles around the Fuel Sending Unit, replace the Fuel Tank * and proceed with the next step.
* Make sure you transfer the new O-Ring and Fuel Sending Unit from the old Fuel Tank to the new Fuel Tank.
17. Apply Tectyl 517 (Bitumen) Wax Sealer to the Fuel Sending Unit Mounting Flange area as follows:
a. Completely clean and dry off (with shop air) the Mounting Flange area.
b. Then, apply ONLY Tectyl 517 (Bitumen) Wax Sealer (999MP-9G001P) around the outer edge of the Fuel Sending Unit Mounting Flange (see Figure 22).
^ Thoroughly shake the can of Wax Sealer to ensure complete mixing.
18. Remove all Rubber Caps and the Connector Covers from the Fuel Tank/Sending Unit.
19. Re-install the fuel tank. Refer to the "FE" section in the applicable Service Manual.
IMPORTANT:
^ Make sure the hoses removed from the fuel tank are correctly installed to the same pipes they were removed from.
^ Make sure the Fuel Sending Unit Wire Harness Connectors are securely locked into position.
^ Make sure all Fuel/EVAP hoses are in good condition (no cracks, splits, etc.) and are securely reconnected to prevent leaks.
20. Re-assemble all previously removed components in the reverse order you removed them.
21. Start the vehicle and confirm proper engine running and fuel gauge operation.