Need help with FPR

There are a few things that could potentially be causing your issues with the AEM 25-302BK Fuel Pressure Regulator (FPR):

1. Incorrect Installation: It's possible that the FPR may not be installed correctly. Check to ensure it is installed according to the instructions provided with the regulator and that all connections and fittings are secure.

2. Faulty FPR: It's somewhat rare, but you may have received another faulty regulator. This could be checked by installing a different regulator and observing if the issue persists.

3. Issues with Fuel Pump: If your fuel pump isn't able to provide adequate pressure, the regulator may not be able to increase pressure correctly. Ensure your fuel pump is working properly.

4. Blocked or Leaking Lines: If the lines going to or from the regulator are blocked or leaking, this could cause issues with pressure regulation.

If you've gone through all these possibilities and are still experiencing issues, it might be best to consult with a professional mechanic or a specialist in fuel systems. They can better diagnose the issue through hands-on inspection and testing.

Apologies for any confusion caused. You are correct; the adjustment of the fuel pressure regulator (FPR) typically involves turning the adjustment stem, often with a hex key or similar tool, rather than the locking screw. The locking screw is designed to secure the adjustment in place once you have set the desired fuel pressure.

If you are unable to adjust the fuel pressure despite turning the adjustment stem, there could be a mechanical issue with the regulator or a potential problem with the specific model you are using. It would be helpful to consult the manufacturer's instructions or reach out to their technical support for guidance on proper adjustment procedures and any known issues or troubleshooting steps specific to the AEM 25-302BK regulator.

I apologize for any confusion caused by my previous response.