Fuel System Pressure Test
- Remove cap from the pressure test port in fuel rail. See Fig 1 . Using a shop towel to absorb any spilled fuel, connect a 0-60 psi (0-4.22 kg/cm2 ) fuel pressure gauge to pressure fitting on fuel rail. Dispose of shop towel properly. Disconnect vacuum hose from fuel pressure regulator. Start engine.
- Pressure should be approximately 39 psi (2.74 kg/cm2 ) with vacuum hose disconnected and 31 psi (2.18 kg/cm2 ) with vacuum hose connected to fuel pressure regulator.
- If fuel pressure is not 8-10 psi (.56-.70 kg/cm2
) higher with vacuum hose disconnected from fuel pressure regulator, inspect vacuum hose for blockage, leaks, kinks or other damage.CAUTION: Fuel pressure will rise as high as 95 psi (6.7 kg/cm2 ) when fuel return line is pinched shut. Turn engine off IMMEDIATELY after pinching off fuel return line.
- If fuel pressure is low, restart vehicle and let engine idle. Momentarily pinch hose section of fuel return line and IMMEDIATELY turn engine off. Note pressure reading on gauge.
- If fuel pressure rises, replace fuel pressure regulator. If fuel pressure remains low, inspect fuel supply line, fuel filter, and fuel rail inlet for blockage. If fuel pressure rises above specifications, check fuel return line for kinks or blockage.