Dakota R/T 2WD V8-5.9L VIN Z LDC (1999)
6. Observe test gauge. Normal operating pressure should be 339 kPa ± 34 kPa (49.2 psi ± 5 psi).
7. Shut engine off.
8. Pressure should not fall below 30 psi for five minutes.
9. 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.
10. Again, start engine and bring to normal operating temperature.
11. Shut engine off.
12. Testing for fuel injector or fuel rail leakage: Clamp off the rubber hose portion of Adaptor Tool between the fuel rail and the test port "T" on
Adapter Tool. If pressure now holds at or above 30 psi, a fuel injector or the fuel rail is leaking.
13. Testing for fuel pump check valve, filter/regulator check valve or fuel tube/line leakage: Clamp off the rubber hose portion of Adaptor Tool
between the vehicle fuel line and test port "T" on Adapter Tool. If pressure now holds at or above 30 psi, a leak may be found at a fuel tube/line. 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.
