Fuel Pressure Regulator
- Ensure ignition is off. Connect fuel pressure gauge to Schrader valve on fuel rail. Ensure manifold vacuum supply tube is connected to fuel pressure regulator. Start engine, and run it for 10 seconds. Stop engine, and wait 10 seconds. Start engine, and operate it for 10 seconds. Stop engine, and remove pressure regulator vacuum hose. See Fig 1. Check vacuum port for fuel.
Courtesy of FORD MOTOR CO.
- If fuel is present, replace fuel pressure regulator and repeat test. If fuel is not present, plug pressure regulator vacuum hose. Observe fuel pressure while driving vehicle and accelerating heavily. If fuel pressure remains at 27-48 psi, go to next step. If fuel pressure does not remain at 27-48 psi, check fuel filter. If filter is okay, replace fuel pump. If filter is dirty, replace filter and recheck system.
- Remove plug from vacuum hose, and connect hose to pressure regulator. Install vacuum gauge to intake manifold. Start engine, and observe fuel pressure gauge and vacuum gauge readings. Increase engine speed. Fuel pressure gauge reading should increase as vacuum gauge reading decreases and vacuum gauge reading should increase as fuel pressure gauge decreases.
- If gauges responds as specified, no fault is present in fuel system. Check for other causes of driveability symptoms. If gauges do not respond as specified, turn ignition off. Remove vacuum hose from fuel pressure regulator, and plug hose. Install a vacuum pump to pressure regulator. Start engine, and observe fuel pressure. Apply vacuum.
- If fuel pressure changes as vacuum is applied, check and repair vacuum system. If fuel pressure does not change as vacuum is applied, replace fuel pressure regulator.