Fuel Pump Pressure Test (4.2L & 5.9L)
- Inspect for kinked or bent fuel tubes or hoses or leaks in supply tubes or hoses. Remove air cleaner assembly. Disconnect fuel inlet fitting at carburetor. Disconnect fuel return hose at fuel filter and plug nipple on filter. Remove any spilled fuel from engine.
- Connect pressure gauge, restrictor and flexible hose between filter and carburetor. Position flexible hose and restrictor so fuel can be discharged into an appropriate graduated container. Operate engine at idle speed and discharge fuel into graduated container by momentarily opening hose restrictor.
- Close hose restrictor, allow pressure to stabilize and note pressure reading on gauge. See FUEL PUMP PRESSURE SPECIFICATIONS table. If pump pressure is not to specifications, and fuel tubes and filter are in satisfactory condition, replace pump. If pump pressure is to specification, perform capacity test.
FUEL PUMP PRESSURE SPECIFICATIONS
| Application | psi (kg/cm2 ) |
|---|---|
| 4.2L TBI | 4-5 (2.8-3.4) |
| 5.9L PFI | 5-6.5 (3.4-4.5) |