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    2002 International MD/HD 4300 7.6L Turbo Diesel 6cyl

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    Ford Excursion, Expedition, Lincoln Navigator 2000-2005

    Oil Temperature Sensor

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    Operation



    The engine oil temperature (EOT) sensor changes resistance in response to the changing temperature of the engine oil. This sensor is located on the high pressure oil pump used to fire the fuel injectors on the 7.3L DIT diesel engine. The EOT sensor is a standard thermistor type sensor like an ECT or IAT. The EOT resistance decreases as the oil temperature increases providing the PCM with a signal relevant to the temperature of the engine oil.

    6.0L Diesel Engine

    The EOT sensor is a thermistor whose resistance decreases as engine oil temperature increases. The EOT signal is used by the PCM to calculate fuel quantity, injection timing, and glow plug operation. At low ambient air temperatures and an oil temperature of less than 70°C (158°F), low idle is increased to maintain stable idle quality. Fuel quantity and timing is controlled throughout the total operating range to provide adequate torque and power.

    Gasoline Engines

    The EOT sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.

    Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow. Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

    The EOT sensor measures the temperature of the engine oil. The sensor is typically threaded into the engine oil lubrication system. The PCM can use the EOT sensor input to determine the following:



    On variable camshaft timing (VCT) applications the EOT input is used to adjust the VCT control gains and logic for camshaft timing.
     
    The PCM can use EOT sensor input in conjunction with other PCM inputs to determine oil degradation.
     
    The PCM can use EOT sensor input to initiate a soft engine shutdown. To prevent engine damage from occurring as a result of high oil temperatures, the PCM has the ability to initiate a soft engine shutdown. Whenever engine RPM exceeds a calibrated level for a certain period of time, the PCM begins reducing power by disabling engine cylinders
     

    Removal & Installation



    1. Disconnect the negative battery cable.
    2.  
    3. With the vehicle in NEUTRAL, position it on a hoist.
    4.  
    5. Drain the engine oil.
    6.  
    7. Disconnect the Engine Oil Temperature (EOT) sensor electrical connector.
    8.  
    9. Remove the EOT sensor. Discard the O-ring seal.
    10.  

    To install:

    1. To install, reverse the removal procedure and note the following:
      1. Install a new O-ring seal. Lubricate the new O-ring seal with clean engine oil prior to installation.
      2.  
      3. Tighten the EOT sensor to 15 ft. lbs. (21 Nm).
      4.  

    2.  

    6.0L Diesel Engine

    WARNING
    Make sure the ignition switch is in the OFF position prior to working on the electronic engine controls.

    1. Turn the ignition switch to the OFF position.
    2.  
    3. Disconnect the engine oil temperature (EOT) sensor.
    4.  
    5. Remove the EOT sensor.
    6.  

    To install:

    1. To install, reverse the removal procedure and note the following:
      1. For early build vehicles, tighten to 9 ft. lbs. (12 Nm).
      2.  
      3. For late build vehicles, tighten to 13 ft. lbs. (18 Nm).
      4.  

    2.  

    Testing



    1. Turn the ignition switch OFF.
    2.  
    3. Disconnect the wiring harness from the EOT sensor.
    4.  
    5. Measure the resistance between the sensor terminals.
    6.  
    7. Compare the resistance reading with the accompanying chart.
    8.  
    9. If the resistance is not within specification, the EOT may be faulty.
    10.  
    11. Connect the wiring harness to the sensor.
    12.  

    6.0L Diesel Engine

    NOTE
    An EOT signal detected out of range, high or low, by the PCM causes the PCM to substitute a temperature based on the ECT to be used for operating purposes.



    Click image to see an enlarged view

    Fig. 6.0L Two Pin Sensor Connector view

    1. Checking the EOT sensor voltage versus resistance:

      Disconnect the EOT sensor connector.
       
      Connect an ohmmeter between the EOT sensor terminals.
       
      With a cold engine measure and note the EOT sensor resistance.
       
      Reconnect the EOT sensor electrical connector.
       
      Start and run the engine to reach proper operating temperature.
       
      Turn off engine and disconnect EOT sensor electrical connector.
       
      Measure and note the reading.
       
      Compare both readings to the temperature -resistance chart.
       
      If the readings do not approximate those in the chart suspect a faulty EOT sensor.
       

    2.  
    3. Checking the EOT Sensor
      NOTE
      Check the cooling system for proper operation.



      Click image to see an enlarged view

      Fig. Excursion Temperature Versus Resistance Chart



      Make sure the engine is at operating temperature.
       
      Turn the ignition switch on engine off.
       
      Install scanner and access the EOT Pid.
       
      Monitor EOT Pid while tapping on sensor.
       
      If the EOT fluctuates or decreases more than 68°F-20°C (3.82 volts).
       
      Replace EOT sensor.
       

    4.  

     
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