FDM & Fuel Pressure
IF THE IMAGE IS TOO SMALL, click it.
Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.
The FDM connector shown is for '94-96; '90-93 use the older connector (WPT454) that mounts directly to the FDM plate.
For the 5.0L, 5.8L and 7.5L EFI engines, the in-tank mounted high pressure fuel pump is capable of supplying 105 liters (27.7 gallons) of fuel per hour at a working pressure of 270.0 kPa (39 psi). For the 4.9L EFI engine, the pump can supply 90 liters (23.7 gallons) per hour at 380 kPa (55 psi). The pump has an internal pressure relief valve to provide overpressure protection in the event the fuel flow becomes restricted. Overpressure is restricted to 850 kPa (123 psi).
The 4.9L will run fine with the same pressure as the V8s.
Test pressure at the fuel rail test port with a temporary screw-on pressure meter. Do not use push-on or permanently-mounted meters or gauges. NOTE: If no pressure is detected in fuel lines during test procedure, fuel pump should not be powered in excess of three minutes to avoid possible overheating of pump.
.
The DLC pinout at the bottom of this diagram DOES NOT APPLY TO '96 trucks since they're OBD-II. The '87-95 DLC is located under the L hood hinge. For more info, see these:
.
See this FSA:
.
...& this TSB:
To temporarily or permanently convert a '90-up 2-tank truck to a single tank with no damage & virtually no cost, read this caption:
See also:
MotorCraft 2016 Wiring Pigtail Guide 
