Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1985 Merkur XR4Ti AutomaticFACTORY OEM SERVICE PROCEDURE
High Pressure Fuel Pump Test
- Separate wiring connector at high pressure fuel pump. Have a helper turn ignition switch to "RUN" position and listen at fuel tank for low pressure pump "buzz".
- If high and low pressure pumps are okay, connect pressure gauge to verify fuel delivery. If necessary, see FUEL PUMP PRESSURE TEST. If low pressure pump does not operate, go to test 3).
- Lower fuel tank. Disconnect fuel pump wiring connector and connect test light from ground to Black/Red wire in harness side of wiring connector. Have helper turn ignition switch to "RUN" position and watch test light. If light comes on for about one second and then goes off, test is okay. Go to test 5).
- If test light does not light, repair open in feed circuit. Go back to test 1) to verify test. See Fig 1 .
- Connect jumper wire from pump ground terminal to a clean underbody ground and connect another jumper from pump feed terminal to alternator output terminal. If pump operates, test is okay. Go to test 6). If pump does not operate, replace low pressure pump. Retest system.NOTE: Ensure last connection is at alternator output terminal.
- Using an ohmmeter, check for continuity between a clean underbody ground and ground wire in harness. There should be no continuity. If test is not okay, repair open in pump ground wire. Go to test 7).
- Separate high pressure pump wiring connector and connect test light from ground to Black/Red wire in harness side of wiring connector. Have helper turn ignition switch to "RUN" position and watch test light. If light comes on for about one second, test is okay. Go to test 8). If test is not okay, repair open in feed circuit.
- Connect jumper wire from pump ground terminal to a clean underbody ground and connect another jumper from pump feed terminal to alternator output terminal. If pump operates, test is okay. If pump does not operate, replace high pressure pump. Retest system.
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.