1987 Merkur XR4Ti AutomaticFACTORY OEM SERVICE PROCEDURE

Fuel Pump Circuit

  1. Turn ignition on and listen for a short period of high pressure pump "buzz". If pump operates, disconnect pump wires. Turn ignition on again and listen for a short period of low pressure pump (in fuel tank) "buzz". If pump operates, system is okay.
  2. If pumps do not operate, check inertia switch, in-line fuse, fuel pump relay, fuel pump wiring and grounds. Turn ignition on. Using a test light, check for battery voltage at both inertia switch wires. If light comes on at both wires, switch is good. Go to next step.
  3. Locate fuse holder under panel and check fuse. If fuse is blown, replace fuse. See Fig 1 . If fuse is okay, go to next step.
  4. Remove fuel pump relay from fuse panel. Using an ohmmeter, check for continuity between fuse terminal and relay terminal No. 87 in panel. If there is continuity, go to next step. If there is no continuity, repair open in circuit. See Figure .
  5. Connect test light from ground to relay terminal No. 30 in panel. If light is on, go to next step. If light is off, repair open in circuit. See Figure .
  6. Connect test light from ground to relay terminal No. 86. Turn ignition on and watch test light. If light is on, go to next step. If light is off, repair open in circuit.
  7. Using an ohmmeter, check for continuity between relay terminal No. 85 and ECA pin No. 22. If there is continuity, replace fuel pump relay. If there is no continuity, repair open in circuit.
Fig 1: Location of In-Line Fuse
G62296
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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.