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Differential Pressure Regulator

  1. Close valve on fuel pressure tester and relieve pressure. Disconnect harness connector at differential pressure regulator. Energize fuel pump and note fuel pressure. Fuel pressure should be 4.3-7.3 psi. (.3-.5 kg.cm2 ) below fuel system pressure in step 3) of FUEL SYSTEM PRESSURE test.
  2. If fuel pressure difference is not okay, remove small diameter fuel line No. 1 from fuel pressure regulator and place in container. Plug fuel line opening on fuel pressure regulator.
  3. Using remote control, energize fuel pump for one minute and measure quantity of fuel in container. Fuel captured in container should be 130-150 ccs. If fuel quantity is less, replace fuel pressure regulator. Reconnect fuel line to fuel pressure regulator.
  4. Connect multimeter to differential pressure regulator. See Figure . Disconnect ignition coil wire and ground. Disconnect CTS harness connector and insert 15,000 ohm side of Bridge Adapter (VW1490 ) into CTS harness connector. See Figure .
  5. Crank engine for about 5 seconds and leave ignition on. Using remote control, energize fuel pump and note reading on fuel pressure gauge. Fuel pressure must be 18.9-23.2 psi (1.4-1.6 kg/cm2 ) below fuel system pressure in step 3) of FUEL SYSTEM PRESSURE test.
  6. If fuel pressure difference is not okay, replace differential pressure regulator. If fuel pressure difference is okay, check wiring harness and ECU.