AEM 25-302BK Universal Adjustable Fuel Pressure Regualtor - Manual (Page 3)

WARNING!!!
The AEM adjustable fuel pressure regulator has been set to 40psi using a
typical fuel pump and a perfect running fuel system. Due to the differences on
vehicle fuel pressure on different applications it is
highly recommended
that you adjust the fuel pressure on your vehicle.
WARNING!!!
Read and understand these instructions BEFORE attempting to install this product
• Do not smoke while working on the fuel system.
• Keep open flames or sparks away from your work area.
• Be sure to relieve fuel pressure while engine is off.
• Disconnect the battery before working on the fuel delivery system.
1) Installation of the AEM Universal Fuel Pressure Regulator
Note: The AEM fuel pressure regulator has the .100” orifice installed in the regulator and is set to
40psi. All adjustments of the pressure regulator will be explained in a later portion of the instructions.
a) The AEM universal fuel pressure regulator is designed with the mounting bracket as a bolt on component
to the regulator body. If you desire, the regulator can be bolted directly to the car using the four threaded
holes at the back of the regulator which are tapped with a 10-32 thread.
i)
Install the mounting bracket to the regulator using the four supplied allen head screws.
ii) Mount the fuel regulator on a flat surface.
iii) The diameter of the mounting holes on the bracket are ¼”. On the last page of the instructions will be a
mounting template, which should be used to mount the fuel regulator.
b) The two inlet ports are tapped with a 9/16-18 thread. The fuel pressure gauge port is tapped with a 1/8-27
NPT.
c) The outlet port is located at the bottom of the fuel pressure regulator. It has a 9/16”-18 thread. You may
purchase a 7mm barb fitting from AEM part number 25-390.
d) Connect the vacuum hose to the top of the fuel pressure regulator. (Hose size is a 3/16” or 5mm)
2) Finishing touches
a) Connect the negative battery terminal.
b) Turn the ignition or fuel pump switch to the on position for approximately two seconds. Do not operate the
starter. Then turn the ignition switch to the off position.
c) Repeat this procedure three times, and then check all fuel system components that were removed during
installation for any signs of fuel leakage.
d) If there are signs of leakage you MUST correct the leak before proceeding.
If there are no signs of leakage, then start engine and again check for leaks. If there is any sign of leaking you
MUST repair the leak before driving the vehicle
3) Pressure and orifice adjustments
Note: The AEM adjustable fuel pressure regulator can be fine tuned for your application. These
adjustments will be covered in this section. A fuel pressure gauge needs to be used for precise tuning.
a) When fuel pressure adjustments are to be made, loosen the jam nut on the top of the AEM fuel pressure
regulator and either tighten or loosen the set screw.
i)
When loosening the jam nut a 3/8” wrench should be used.
ii) When tightening or loosening the set screw a 3/32” allen key should be used.
(1) To increase fuel pressure turn the set screw in a clockwise rotation.
(2) To decrease fuel pressure turn the set screw in a counter-clockwise rotation.
b) When orifice changes are to be made, remove the fuel pressure regulator using the steps in section 4 in
reverse order. When this is completed, remove the six bolts from the top of the fuel pressure regulator and
use a 3/8” socket to remove the orifice in the regulator and replace with a different size orifice.
i)
When removing the six bolts from the top of the fuel pressure regulator a 9/64” allen key should be
used.
(1) Torque to 24lbf-in.
(2) There is a constant pressure applied to the diaphragm by the spring inside the fuel regulator make
sure parts do not get lost upon removal of these bolts.
ii) When ever the regulator is dis-assembled check the diaphragm for any wear and tear, which may
cause a fuel pressure problem.
(1) If the diaphragm is damaged contact AEM to purchase a replacement diaphragm.
iii) When removing the orifice a 3/8” socket should to be used.