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2.3L Engines

  1. Check fuel tank for adequate fuel supply. Check for fuel leakage at all fittings and lines.
  2. Check for electrical continuity to the fuel pump(s). On a single pump system, disconnect electrical connect just forward of the fuel pump inlet. On dual pumps, disconnect electrical connector to fuel pumps at high pressure pump module. Connect voltmeter to body wiring harness connector. Turn ignition key to "ON" position while watching the voltmeter.
  3. Voltage should rise to battery voltage and then return to zero voltage after approximately one second. If voltage is not as specified, check inertia switch and electrical system. Connect ohmmeter to pump wiring harness connector. If no continuity is present, check continuity directly at pump terminals. If no continuity is at pump terminals, replace pump(s). If continuity is present at terminals, service and replace wiring harness.
  4. For dual pump systems only, connect the ohmmeter across the body wiring harness connector. If continuity is present (about 5 ohms), low pressure pump circuit is electrically okay.
  5. For dual pump systems only, if no continuity is present in step 4), it is necessary to remove fuel tank and check for continuity at fuel pump/pump sender flange terminals. If no continuity at pump flange terminals is present, replace the assembly. If continuity is present at pump but not in step 4), service or replace the wiring harness in the low pressure pump.
  6. Check operation of fuel pump(s). Disconnect return line at fuel rail. Use care to avoid spillage. Connect hose from fuel rail fitting to a calibrated container of at least one quart. Connect pressure gauge to fuel diagnostic valve on fuel rail. Disconnect the electrical connector to the electric fuel pump(s) located just forward of the pump outlet.
  7. Connect auxiliary wiring harness to the electrical connector to the fuel pump. Energize the fuel pump(s) for 10 seconds by connecting the auxiliary wiring harness to a fully charged 12-volt battery. Observe pressure while energized. If no pressure, check polarity of wiring harness and also check terminal connections at fuel pump(s).
  8. Allow fuel to drain from hose into container and observe the volume. The fuel pump(s) are operating properly if; fuel pressure reaches 35-45 psi (2.5-3.2 kg/cm2 ), fuel flow is a minimum of 7.5 oz (220 cc) for a single pump system; 9.5 oz. (280 cc) for a dual pump system, in 10 seconds, and fuel pressure remains at a minimum of 30 psi (2.1 kg/cm2 ) immediately after di-energizing.
  9. If all 3 conditions are met, the fuel pump is operating normally. If pressure condition is met but flow is not, check for blocked filter(s) and fuel supply lines. After correcting any blockage, recheck using step 8). If flow conditions are still not met, replace fuel pump.
  10. If both pressure and flow conditions are met, but pressure will not maintain after de-energizing, check but leakage at the regulator or injectors. If both check okay, replace fuel pump.
  11. If no flow or pressure is seen, the fuel system should be checked as in step 9). If no trouble is found, replace the fuel pump, drop the fuel tank and replace the fuel filter on the filler neck tube or on the low pressure pump, depending on application.
  12. On a system with 2 fuel pumps, if hot fuel problems exist or system is noisy, check the low pressure in-tank pump as follows. Remove inlet push connect fitting and line from high pressure pump assembly.
    CAUTION: Raise end of fitting above level of fluid in tank to prevent a siphon action.
  13. Connect hose from fuel tank to a calibrated container of at least one quart. Place ignition key in the "RUN" position until fuel pump times out (approximately one second). Check container for presence of fuel (if necessary, lift container to prevent siphon action). The amount of fuel should be a minimum of 1.5 oz. (50 cc) for one second of operation.
  14. If no fuel is present, recycle ignition key. If no fuel is present, check for a pinched line between the fuel tank and fitting, and then proceed to drop the fuel tank.
  15. Connect a voltmeter to the chassis electrical connector from the fuel pump and turn ignition key to "ON" position. Voltage should rise to battery voltage for one second and then return to zero volts. If voltage is as specified and electrical connector was okay at pump, replace fuel pump assembly and repeat low pressure fuel pump test. If no voltage is present, service electrical circuit in vehicle.
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