Aeromotive 14127 - 99-04 5.4L LIGHTNING_HARLEY FUEL RAIL SYSTEM - Manual (Page 5)

31. Reassemble the vehicle using the reverse of the foregoing removal procedure.
32. Remove the 1/8 NPT pipe plug from the either the fuel pressure regulator or fuel supply adapter tee
fitting and attach a suitable fuel pressure gauge.
Ensure that any spilled gasoline and any gasoline soaked shop towels are cleaned up and
removed from the vicinity of the vehicle!
33. Reconnect the battery and turn the ignition to the ON position WITHOUT starting the car. After
several seconds, check the fuel pressure. If there is no fuel pressure, turn the ignition key to the OFF
position, wait one minute, return the ignition to the ON position, and recheck the fuel pressure.
Repeat this ignition OFF and ON procedure until the fuel pressure gauge registers fuel pressure.
With the fuel pressure gauge registering fuel system pressure, check for fuel leaks from and
around the Aeromotive regulator, fuel rails, all fuel lines and connections! If any fuel leaks are
found, turn the ignition key to the OFF position, remove any spilled fuel and repair the leak before
proceeding!
34. Once the fuel pressure gauge registers fuel system pressure and there are no fuel leaks, start the
engine and adjust the regulator to the desired fuel pressure. Turning the adjustment screw clockwise
will increase fuel pressure. OEM regulators are typically set at approximately 43 psi, without the
vacuum line attached. The fuel pressure adjustment range for this regulator is 35-75 psi and we
recommend setting the static pressure (no vacuum) at 40 psi.
Due to the confined nature of modern OEM vehicles Aeromotive realizes that the fuel pressure regulator
may be inconvenient to adjust in some applications. We feel that this small inconvenience is worth it in
providing you with an optimal fuel system.
35. Once the desired fuel pressure is achieved, tighten the regulator adjustment jam nut and attach the
vacuum line.
36. Turn off the engine and allow it to cool. If you do not want to keep the fuel pressure gauge on the
vehicle, relieve the fuel system pressure as instructed in the appropriate vehicle service manual.
Remove the fuel pressure gauge and reinstall the 1/8 NPT pipe plug, using thread sealant.
37. Test drive the car to insure proper operation and re-check the fuel system for leaks. If any leaks are
found, immediately shutoff the engine and repair the leak(s)!