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Troubleshooting Teleflex Fuel Gauges

Does the Gauge Work?

To see if the gauge is operating correctly:
  1. Remove the gauge's sender wire. Turn on the power. The pointer of whatever gauge you are checking should be at the position shown in the upper portion of the diagram at right.

  2. Next, take a short wire and connect to sender terminal and ground terminal (shorting sender terminal to ground). Gauge pointer should be at the position shown in the lower portion of the diagram.

  3. To test senders, the resistance values are shown at minimum and full gauge scales.

Fuel Systems (Marine)

  1. Voltage - "I" to "G" terminal - 10 to 16 volts.
  2. Test gauge as follows: Connect "hot" wire to the "I" terminal and ground wire to "G" terminal. Remove sender (usually pink) wire from back of gauge. Gauge should read below "EMPTY". Next, add a short wire from the gauge's "S" (sender) terminal to ground. Gauge should read above "FULL." If the pointer sweeps back and forth, gauge is OK.
  3. The sender can be tested by checking its resistance with a volt/ohm test meter (use analog meter) as follows:
    1. Remove sender (usually pink) wire from sender.
    2. Connect two test meter wires to two sender terminals (or center terminal & flange if sender has only one terminal).
    3. Move float arm by hand. Approximate values: Empty = 240 ohms, 1/2 = 103 ohms, Full = 33 ohms. (Teleflex sender: rheostat housing installed upside down will cause gauge to read backwards. See illustration.)
  4. Sender resistance tolerances at full may cause the gauge to read 2-3 pointer widths either side of the full mark.
  5. The sender will accurately operate only one standard gauge at a time. It is not designed for dual station use with standard gauges.
  6. Gauge will not operate accurately from more than one sender at a time. Some installations use a switch to connect one gauge to various tanks, one at a time.
  7. Sender will not operate in water tanks. Rheostat will become electrically "open".
  8. Be certain sender dimensions are adjusted per the instruction sheet.
  9. If sender is "open" (infinite resistance) gauge will read below empty. If sender is shorted (0 resistance) gauge will read above "FULL".
  10. Some "bowing" of the flange may occur when the 5 mounting screws are tightened. The gasket under the flange will normally seal the flange properly, but do not overtighten the mounting screws.
  11. Sender must be grounded, or gauge will always read "EMPTY."
  12. If sender is installed in a tank not designed for a sender, care must be taken to seal screw threads. Sealant under screw head is also advisable. Sealant must withstand gas and diesel fuels.

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