IDG = Integrated Drive Generator. It's an alternator which is better known as "engine generator"; that device that provides electric power when the running engine turns it fast enough.
As for the fuel spar valve, it is upstream of the engine. It is a DC motor Hot Battery Bus-powered. The engine mounted EFSOV is fuel operated, solenoid controlled Battery Bus-powered. Fuel is delivered under pressure from fuel pumps located in the fuel tanks. The fuel flows through a fuel spar shutoff valve located at the engine mounting wing stations. The fuel passes through the first stage engine fuel pump where pressure is increased. It then passes through two fuel/oil heat exchangers where IDG oil and main engine oil heat the fuel. A fuel filter then removes contaminants. Fuel automatically bypasses the filter if the filter becomes saturated. Before the fuel bypass occurs, the fuel FILTER BYPASS alert illuminates on the fuel control panel.
The second stage engine fuel pump adds more pressure before the fuel reaches the hydro-mechanical unit (HMU). To meet thrust requirements, the EEC meters fuel through the HMU. The spar fuel shutoff valve and engine fuel shutoff valve allow fuel flow to the engine when both valves are open. The valves are open when the engine fire warning switch is in and the start lever is in IDLE. Both valves close when either the start lever is in CUTOFF or the engine fire warning switch is out. SPAR VALVE CLOSED and ENG VALVE CLOSED lights located on the overhead panel indicate valve position.
Fuel flow is measured after passing through the engine fuel shutoff valve and is displayed on the display unit. Fuel flow information is also provided to the FMS.