The diaphragm is an integral part of any adjustable fuel pressure regulator (AFPR). The regulator uses a diaphragm and spring combination within it's housing with a vacuum source on the top side of the diaphragm to counteract the spring pressure when high demand dictates that higher fuel pressure is necessary.
An indication that your AFPR needs to be replaced is a sudden loss of all fuel pressure immediately after shutting off the engine. Another sign is difficulty starting the engine after it has been sitting for a few hours or more. These could also be signs that the fuel pump is leaking fuel back into the tank or a fuel leak somewhere in your system.
There are many different brands of AFPR's on the market for DSM's. Mine is the Buschur Racing modified SX Racing "Bolt-on" AFPR. Buschur Racing doesn't list replacement diaphragms on there website but I called them up and they were able to send me one. Other companies sell rebuild kits like this one from Aeromotive, which includes a replacement diaphragm and 4 new bolts.
Replacing the diaphragms is a very easy task. The pictures in this article are all of the BR/SX AFPR but most other regulators are setup the same way.
Note: It might be necessary to release the fuel pressure on the system before changing the diaphragm. However if your pressure is already at zero (as in my case) it can be skipped.
Step 1 Clean the area around your regulator. You dont want any dirt falling into the body of the regulator when you remove the lid. Also depending on where your regulator is installed it may be necessary to move a few things to gain access. Mine is installed at the end of the fuel rail is extremely easy to get to.
Step 2 Remove the lid. There are 4 allen head bolts holding the lid to the body. Use caution when removing these, as there is a spring under the lid.
Step 3 Move the spring and cap out of the way.
Step 4 Remove the diaphragm off the body of the regulator. Peel the diaphragm off using caution in case the fuel system is still under pressure.
Step 5 Reinstall. Make sure the surface is clean and install the new diaphragm. Place the spring and cap back in the center of the regulator and reinstall the lid. Be careful not to over torque the bolts. Verify that the fuel pressure is still set. Fuel pressure should be:
1G MT = 37psi
1G A/T = 43psi
1G NT = 48psi
2G All = 43psi
I hope this helps!
If you have any suggestions please pm me and I will update this article.
An indication that your AFPR needs to be replaced is a sudden loss of all fuel pressure immediately after shutting off the engine. Another sign is difficulty starting the engine after it has been sitting for a few hours or more. These could also be signs that the fuel pump is leaking fuel back into the tank or a fuel leak somewhere in your system.
There are many different brands of AFPR's on the market for DSM's. Mine is the Buschur Racing modified SX Racing "Bolt-on" AFPR. Buschur Racing doesn't list replacement diaphragms on there website but I called them up and they were able to send me one. Other companies sell rebuild kits like this one from Aeromotive, which includes a replacement diaphragm and 4 new bolts.
Replacing the diaphragms is a very easy task. The pictures in this article are all of the BR/SX AFPR but most other regulators are setup the same way.
Note: It might be necessary to release the fuel pressure on the system before changing the diaphragm. However if your pressure is already at zero (as in my case) it can be skipped.
Step 1 Clean the area around your regulator. You dont want any dirt falling into the body of the regulator when you remove the lid. Also depending on where your regulator is installed it may be necessary to move a few things to gain access. Mine is installed at the end of the fuel rail is extremely easy to get to.
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Step 2 Remove the lid. There are 4 allen head bolts holding the lid to the body. Use caution when removing these, as there is a spring under the lid.
You must be logged in to view this image or video.
Step 3 Move the spring and cap out of the way.
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Step 4 Remove the diaphragm off the body of the regulator. Peel the diaphragm off using caution in case the fuel system is still under pressure.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
Step 5 Reinstall. Make sure the surface is clean and install the new diaphragm. Place the spring and cap back in the center of the regulator and reinstall the lid. Be careful not to over torque the bolts. Verify that the fuel pressure is still set. Fuel pressure should be:
1G MT = 37psi
1G A/T = 43psi
1G NT = 48psi
2G All = 43psi
I hope this helps!
If you have any suggestions please pm me and I will update this article.
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