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The Fuel Temperature Sensor (FTS) is installed into the secondary fuel filter. See Figure 20415 . The FTS sends an electrical signal to the ECM indicating fuel inlet temperature. The ECM uses this information to calculate fuel consumption. ‪

Engine Fuel Temperature Sensor

On natural gas engines with the low pressure fuel system, the fuel temperature sensor is located in the fuel mixer housing. See Figure 33385 . ‪

1. Fuel Temperature Sensor ‪

2. Mixer Housing ‪

Fuel Temperature Sensor Series 50G Engine with Low Pressure Fuel System

On Series 50G engines with the high pressure fuel system the fuel temperature sensor is located in the PSV. See Figure 34515 . ‪

1. Fuel Temperature Sensor ‪

5. Air Inlet Elbow ‪

2. PSV ‪

6. Low Pressure Regulator ‪

3. Fuel Mixer ‪

7. Air Temperature Sensor ‪

4. Throttle ‪

8. Fuel Pressure Sensor ‪

9. Fuel Inlet Tee Fitting ‪

Fuel Temperature Sensor Series 50G Engine with High Pressure Fuel System

Repair or Replacement of Fuel Temperature Sensor

The FTS is non-serviceable and should be replaced as a unit. No adjustment is required. ‪

Removal of Fuel Temperature Sensor

Remove the FTS as follows: ‪

  1. Disengage the locking tang on the two-wire connector. Grasp the body of the connector and gently pull it from the socket.
  2. Use the appropriate wrench on the hex portion of the sensor and unscrew it from the fitting.

Installation of Fuel Temperature Sensor

Install the FTS as follows: ‪

Note: The Fuel Temperature Sensor is an electrical device. Use care in the installation process.

  1. Use Loctite Pipe sealer with Teflon J 26558-92 part of PT-7276 (or equivalent) on all but the first two threads of the FTS to prevent leaks.
  2. Screw FTS into the fitting.
  3. Engage the locking tang.
  4. Turn the ignition to the "ON" position. Observe or read any diagnostic codes. If any code other than 25 is obtained, refer to the DDEC II Troubleshooting Guide , 6SE489, or DDEC III/IV Single ECM Troubleshooting Guide, 6SE497.