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.
Spark Check
- Perform self diagnostic QUICK TEST to check for ignition-related fault codes, and repair as necessary. See QUICK TEST in the appropriate TESTS W/CODES
article in the ENGINE PERFORMANCE section.
- TESTS W/CODES - EEC-V - Continental
- TESTS W/CODES - EEC-V (4.6L)
- All Others
If no fault codes are retrieved, check ignition system wiring harness connectors for corrosion and tight fit. See the appropriate WIRING DIAGRAMS article in the ENGINE PERFORMANCE section. Clean or repair connectors as necessary.
- WIRING DIAGRAMS - Continental
- WIRING DIAGRAMS - 4.6L - Cougar & Thunderbird
- WIRING DIAGRAMS - Town Car
- WIRING DIAGRAMS - 4.6L - Crown Victoria & Grand Marquis
- If wiring and connectors are okay, use Neon Bulb Spark Tester (D89P-6666-A) to check for spark at each spark plug wire while cranking engine. If spark is strong and consistent at each spark plug (one spark per crankshaft revolution), ignition system is okay. If spark is not present, go to IGNITION SYSTEMS in the SYSTEM & COMPONENT TESTING -- EEC-V article in the ENGINE PERFORMANCE section.
Use the Manual With the Right Hardware
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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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