Fuel Pressure Regulator Check

1. Stop engine and disconnect fuel pressure regulator vacuum hose from intake manifold.
2. Plug intake manifold with a rubber cap.
3. Connect variable vacuum source to fuel pressure regulator.
4. Start engine and read indication of fuel pressure gauge as vacuum is changed.

Fig 1: Checking Fuel Pressure Regulator

Courtesy of NISSAN MOTOR CO., U.S.A.

Fuel pressure should decrease as vacuum increases. If results are unsatisfactory, replace fuel pressure regulator.