Adding an AFPR to Jake’s Eclipse

I’ve had a Fuelab AFPR (Adjustable Fuel Pressure Regulator) sitting in my toolbox since mid-summer before we started the timing job. Worse than that, I’ve had my Walbro 255 since I was still working on the old 420a shell. In order to use the 255 with this project, I needed to get the AFPR installed. A Walbro 255 will nearly always overrun the stock fuel pressure regulator on a DSM. Upgrading your fuel system is the first step to preparing for a larger turbo, so it’s been on my high list of things to get done for a while. Surprisingly, installing an AFPR is actually pretty easy.

Parts List

Tool List


  1. Depressurize the fuel system
  2. Reconnect the fuel pump
  3. Remove the strut tower brace if you have one installed
  4. Remove the upper timing cover
  5. Disconnect the vacuum line from the fuel pressure regulator
  6. Remove the fuel line from the end of the fuel pressure regulator (wear eye protection just in case there is still pressure in the line)
  7. Cap off the fuel line, I used some plastic and electric tape
  8. Remove the stock fuel pressure regulator. It has 2 10mm bolts holding it in place and a rubber seal preventing it from leaking. After removing the bolts, a few back and forth twists will help release the seal.
  9. Install the fuel rail adapter
  10. If you haven’t done so yet Make your new fuel line. This will connect your AFPR to the fuel rail adapter. Your old fuel line will connect to the bottom of the AFPR using your push on hose fitting.
  11. Install the fittings and gauges on the AFPR using the AN wrench to prevent damaging them
  12. Mount the AFPR on the firewall. It should come with a bracket, but since I got mine used, I bent a piece of aluminum to make a bracket.
  13. Connect the old fuel line to the push on fitting on the bottom of the AFPR
  14. Connect the new fuel line to the -6AN fitting on the AFPR and connect the other end to the fuel rail adapter.
  15. Tighten everything down
  16. With the vacuum hose still disconnected, start the car
  17. Loosen the top nut on the AFPR and use an allen wrench to turn the bolt on the top of the AFPR until the gauge reads around 43.5 PSI (factory fuel pressure).
  18. Tighten the top nut
  19. Connect the vacuum hose to the barbed NPT fitting on the AFPR. The pressure will now drop with the vacuum applied.
  20. Put the timing cover and strut tower brace back on

Here’s a video we took during the project


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