pressures that are read by the EEC are ambient pressure,  burner pressure, LPC exit pressure, and fan inlet pressure.  Each channel has its own wire color that connects the EEC  to its sensors. Channel A wiring is blue and channel B sensor  signals are green. The non-EEC circuit wire is gray while  the thermocouple signals are yellow. This color coding helps  simplify which sensors are used with each channel. this information to the EEC. The EEC uses a torque motor  driver to control the position of the metering valve in the fuel  metering unit. The EEC uses solenoid drivers to control the  other functions of the FMU. The EEC also controls several  other subsystems of the engine, as shown in  Figure 2-56 ,  through torque motors and solenoids, such as fuel and air oil  coolers, bleed valves, variable stator vanes, turbine cooling  air valves, and the turbine case cooling system.  Each channel of the EEC has seven electrical connections,  three on each side and one on the bottom. Both channels  share the inputs of the two connections on the top of the  EEC. These are the programming plug and test connector.  The programming plug selects the proper software in the  EEC for the thrust rating of the engine. The plug attaches to  the engine fan case with a lanyard. When removing the EEC,  the plug remains with the engine. Each channel of the EEC  has three pneumatic connections on the bottom of the EEC.  Transducers inside the EEC supply the related and opposite  EEC channel with a signal in proportion to the pressure. The  On warm days, thrust is reduced because of the decrease in  air density. This can be compensated for by injecting water  at the compressor inlet or diffuser case. This lowers the air  temperature and increases air density. A microswitch in the  fuel control is actuated by the control shaft when the power  lever is moved toward the maximum power position. The fuel pump receives fuel from the airplane fuel system.  The low pressure boost stage of the pump pressurizes the fuel  and sends it to the fuel/oil cooler (FOC). The fuel flows from  the FOC, through the fuel pump filter element, and then to  the high pressure main stage of the pump. The high pressure  main stage increases the fuel pressure and sends it to the fuel  metering unit (FMU). It also supplies servo fuel to the servo  fuel heater and engine components. Fuel for combustion  (metered fuel) goes through the fuel flow transmitter to  the distribution valve.  [Figure 2-57]  The fuel distribution  valve supplies metered fuel to the fuel supply manifolds.  [Figure 2-58]  The fuel injectors get the metered fuel from the  fuel supply manifolds and spray the fuel into the engine for  combustion.  [Figure 2-59]  The fuel pump housing contains  a disposable fuel filter element. The fuel filter differential pressure switch supplies a signal to the EEC that indicates an almost clogged filter condition. Unfiltered fuel can then  bypass the filter element if the element becomes clogged. Fuel System Operation Water Injection System 2-41 Figure 2-56.  Systems controlled by EEC.  Figure 2-55.  Fuel pump.  PROG PLUG FOC bypass valve ENG AOC valve IDG AOC valve BU GEN AOC valve FMU 2.5 bleed valve TAC valve PMA VSV TCC valves Sensors 2.9 bleed valve NAC zone vent valve