Fuel Pressure Check
- Ensure engine temperature is less than normal operating temperature. If engine is at normal operating temperature, there may be abnormal pressure readings because of hot-soak fuel vaporization. Removing fuel filler cap may reduce effect of fuel vaporization. Turn ignition off. Relieve fuel pressure. See RELIEVING FUEL PRESSURE under FUEL DELIVERY. Install fuel pressure gauge to fuel rail. Install shut-off valves in fuel supply and return lines. Activate fuel pump and bleed air from fuel pressure gauge.
- Allow fuel pressure to stabilize and record fuel pressure. Fuel system pressure should be 35-38 psi (2.4-2.6 kg/cm2 ) at idle. Turn fuel pump off and monitor gauge for changes in fuel pressure. If fuel pressure does not change, go to FUEL INJECTOR BALANCE CHECK . If fuel pressure decreases, close shut-off valve on fuel supply line and check fuel pressure. If fuel pressure decreases, go to next step. If fuel pressure does not decrease, check valve in fuel pump is faulty. Replace fuel pump.
- If fuel pressure continues to decrease, close shut-off valve on fuel return line and check fuel pressure. If fuel pressure does not decrease, replace fuel pressure regulator. If fuel pressure continues to decrease, check fuel system for a leak. Repair as necessary. If no leaks are found, one or more fuel injectors may be leaking. Go to FUEL INJECTOR BALANCE CHECK .