Spark Check
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1994 Mercury Grand Marquis, 1994 Mercury Cougar, 1994 Lincoln Town Car, 1994 Lincoln Mark VIII, and 1994 Ford Thunderbird. However, it is still accessible from the selected car via links, so may be relevant.
- Check the DI system (formerly Thick Film Ignition-IV (TFI-IV) system) for fault codes and repair if necessary. See QUICK TEST in appropriate TESTS W/CODES
article listed below. If no fault codes are retrieved, check ignition system wiring harness connectors for damage, corrosion and tight fit. See Fig 1
.
- TESTS W/CODES - EEC-IV (5.0L) (for Mustang)
- TESTS W/CODES - EEC-V (4.6L) (for Cougar & Thunderbird 4.6L)
- TESTS W/CODES - EEC-IV (4.6L) (all other 4.6L)
- If no fault codes are retrieved and vehicle starts, problem is intermittent, go to appropriate TESTS W/O CODES
article listed below. If no fault codes are retrieved and vehicle is a no-start, connect a high-output spark tester between ignition coil wire and engine ground. Check for spark at coil wire while cranking engine. A consistent Blue spark should be present.
- TESTS W/O CODES - EEC-IV (5.0L) (for Mustang)
- TESTS W/O CODES - EEC-IV (4.6L) (for Crown Victoria, Grand Marquis, Mark VII & Town Car)
- TESTS W/O CODES - EEC-V (4.6L) (for Cougar & Thunderbird 4.6L)
- If spark is present, go to step 4). If no spark is present, remove distributor cap and crank engine to ensure distributor rotates. If okay, check resistance of coil secondary wire. Resistance should be less than 7000 ohms per foot. Service coil wire if necessary and retest. If spark is not present, proceed to appropriate I - SYS/COMP TESTS article listed below or the appropriate TESTS W/O CODES
article in this section listed above.
- SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) (for Mustang)
- SYSTEM/COMPONENT TESTS - EEC-V (for Cougar & Thunderbird 4.6L)
- SYSTEM/COMPONENT TESTS - EEC-IV (4.6L) (all other 4.6L)
- On all models, if a consistent Blue spark is present at coil wire during cranking, inspect distributor cap and rotor for cracks or carbon tracking. Service as necessary and test spark output at spark plugs. If spark is present at spark plugs and engine will not start, go to appropriate TESTS W/O CODES article listed in the previous paragraph.