Mike,
Your residual pressure loss could be due to:
- Defective fuel accumulator.
- Defective fuel pump check valve.
You could test the fuel accumulator by blowing air through and observe any bubbles coming from the bottom. If you have a two-port fuel accumulator, remove the screw during the test.
You will need a pressure gauge installed between the fuel pump and the fuel accumulator to test for the FP check valve. Replace parts only after verifying that they are defective. Do not replace CIS components unless tested and verified to be defective.
Lastly, your WUR-072 is not a vacuum assisted unit and will not work without OXS and ECU. You can use any of these WUR’s for your set-up plus a thermotime valve:
- WUR-033
- WUR-045.
- WUR-069.
- WUR-089.
Tony