Fuel Pump Pressure Test
- Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE in this article. On 2.5L turbo and 3.3L, remove protective cover from service valve on fuel rail. On all others, disconnect 5/16" fuel supply hose from engine.
- Connect Fuel System Pressure Tester (C-4799-A) to fuel rail service valve or fuel line between fuel supply hose and engine fuel line assembly. An Adapter (6433) may be needed on 3.0L.
- Connect Diagnostic Readout Box-II (DRB-II) Tester (C-4805) to self-test connectors and place ignition switch in RUN position. Select ASD FUEL SYSTEM TEST on DRB-II to activate fuel pump and pressurize fuel system. See FUEL PRESSURE SPECIFICATIONS.
- If gauge reading is within specification, pressure is correct and no further testing is required. Reinstall fuel hose using new clamp. Tighten clamp to 10 INCH lbs. (.9 N.m). If fuel pressure is less than specification, proceed to step 5). If fuel pressure is greater than specification, proceed to step 6).
- Install pressure tester in fuel supply line between fuel tank and fuel filter at rear of vehicle. Repeat test. If pressure meets specifications, replace fuel filter. If pressure reading does not change, gently squeeze return hose. If pressure increases, replace pressure regulator. If pressure reading does not change after squeezing hose, pump filter sock is plugged or fuel pump is defective.
- If pressure is greater than specification, remove fuel return hose near fuel tank. Connect substitute hose to body and place other end in clean container. Repeat test.
- If pressure is now correct, check for restricted fuel return line. If pressure reading does not change, replace fuel pressure regulator.
FUEL PRESSURE SPECIFICATIONS
| Application | psi (kg/cm2 ) |
|---|---|
| TBI | 13.5-15.5 (.9-1.1) |
| PFI (Non-Turbo) | 46.0-50.0 (3.2-3.5) |
| PFI (Turbo) | 53.0-57.0 (3.7-3.9) |