Durango 4WD V8-5.9L VIN Z (1998)
6. Shut engine off.
7. Pressure should not fall below 30 psi for five minutes.
8. If pressure falls below 30 psi, it must be determined if a fuel injector, the check valve within the fuel pump module, or a fuel tube/line is leaking.
9. Again, start engine and bring to normal operating temperature.
10. Shut engine off.
11. Testing for fuel injector or fuel rail leakage:
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Clamp off the rubber hose portion of Adaptor Tool between the fuel rail and the test port "T" on Adapter Tool.
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If pressure now holds at or above 30 psi, a fuel injector or the fuel rail is leaking.
12. Testing for fuel pump check valve, filter/ regulator check valve or fuel tube/line leakage:
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Clamp off the rubber hose portion of Adaptor Tool between the vehicle fuel line and test port "T" on Adapter Tool.
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If pressure now holds at or above 30 psi, a leak may be found at a fuel tube/line.
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If no leaks are found at fuel tubes or lines, one of the check valves in either the electric fuel pump or filter/ regulator may be leaking.
NOTE: A quick loss of pressure usually indicates a defective check valve in the filter/regulator. A slow loss of pressure usually indicates a
defective check valve in the electric fuel pump.
The electric fuel pump is not serviced separately. Replace the fuel pump module assembly. The filter/regulator may be replaced separately on
certain applications. Refer to Fuel Filter/Fuel Pressure Regulator Removal/Installation for additional information.