1985 Ford Mustang SVOFACTORY OEM SERVICE PROCEDURE

1.6L Engines

  1. Check fuel tank for adequate fuel supply. Check for fuel leakage at all fittings and lines. Check for electrical continuity to fuel pump. Disconnect electrical connector just forward of the fuel pump inlet. Connect voltmeter to body wiring harness connector. Turn key to "ON" position while watching voltmeter.
  2. 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 continuity tester to pump wiring harness connector. If no continuity is present, check continuity directly at pump terminals. If no continuity is at present at pump terminals, replace pump. If continuity is present, service or replace harness.
  3. Check electric fuel pump operation. Disconnect return line at fuel rail. Use care to avoid fuel 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 located just forward of the pump outlet, if not already disconnected from steps 1) and 2).
  4. Connect auxiliary wiring harness to the electrical connector to the fuel pump. Energize the fuel pump 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. Allow fuel to drain from hose into the container and observe volume.
  5. The fuel pump is operating properly if the fuel pressure reaches 35-45 psi (2.5-3.2 kg/cm2 ), fuel flow is a minimum of 7.5 oz. (220 cc) in 10 seconds, and fuel pressure remains at a minimum of 30 psi (2.1 kg/cm2 ) immediately after de-energization.
  6. If all 3 conditions are met, the fuel pump is operating normally. Check for engine and electrical problems. If pressure condition is met, but flow is not, check for blocked filters and fuel supply lines. After correcting any blockages, recheck. If flow conditions are still not met, replace fuel pump.
  7. If both pressure and flow conditions are met, but pressure will not remain after de-energization, check for leaking regulator or injectors. If both check okay, replace fuel pump. If no flow or pressure is seen, the fuel system should be checked as in step 5). If no trouble is found, replace the fuel pump, drop the fuel tank and replace the fuel filter on the pick-on tube.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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