1. Battery and Electrical System:
* Dead Battery: This is the most frequent culprit. Test the battery voltage with a multimeter. It should read around 12.6 volts when fully charged. Less than 12 volts indicates a weak or dead battery. Try jump-starting it. If it starts and then dies again, the battery is likely bad.
* Loose or Corroded Battery Terminals: Clean the terminals with a wire brush and baking soda and water solution. Make sure they are securely connected.
* Alternator: A failing alternator won't charge the battery, leading to a no-start condition. Test the alternator output voltage while the engine is running. It should be around 13.5-14.5 volts.
* Starter Motor: The starter motor cranks the engine to start it. A faulty starter can result in clicking sounds when you turn the key, slow cranking, or no cranking at all. This might require professional diagnosis and replacement.
* Wiring Issues: Check all wiring connections related to the battery, starter, and ignition system for any damage, looseness, or corrosion. A broken wire can prevent the car from starting.
* Ignition Switch: A faulty ignition switch prevents power from reaching the starter motor. This is less common but possible.
2. Fuel System:
* Empty Fuel Tank: Check the fuel gauge. Sounds obvious, but it's easy to overlook!
* Fuel Pump: The fuel pump delivers fuel to the engine. A faulty fuel pump will prevent the engine from starting. You might hear a humming sound from the fuel pump when you turn the ignition key (listen near the fuel tank). If you don't hear it, the pump may be the problem.
* Clogged Fuel Filter: A clogged fuel filter restricts fuel flow to the engine. Replacing the filter is relatively inexpensive.
* Fuel Injectors: These spray fuel into the engine. Clogged or faulty injectors can prevent starting. This is more difficult to diagnose without specialized tools.
3. Ignition System:
* Distributor (if equipped): Older Mustangs might have a distributor. Issues with the distributor cap, rotor, or ignition coil can prevent starting.
* Ignition Coil: The ignition coil provides the high voltage needed to ignite the fuel-air mixture. A faulty coil will prevent the engine from firing.
* Spark Plugs and Wires: Worn-out spark plugs or damaged spark plug wires can also prevent starting. Inspect them for damage or corrosion.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's position. A faulty sensor prevents the engine from starting.
* Computer (PCM): A faulty PCM can cause a wide range of issues, including a no-start condition. This is usually diagnosed with a scan tool.
4. Other Potential Issues:
* Security System: If the car has an aftermarket or factory security system, it might be preventing the car from starting.
* Neutral Safety Switch: This switch prevents starting unless the car is in park or neutral (automatic transmission).
Troubleshooting Steps:
1. Start with the basics: Check the battery, terminals, and fuel level.
2. Listen for sounds: Any clicking, humming, or unusual noises can provide clues.
3. Visual inspection: Check for any obvious damage to wiring, components, or hoses.
4. Use a multimeter: To test battery voltage, alternator output, and other electrical components.
5. Consult a repair manual: A repair manual specific to a 1997 Ford Mustang will provide detailed troubleshooting information and diagrams.
6. Seek professional help: If you're not comfortable diagnosing the problem yourself, take it to a mechanic.
Without more information about the symptoms (e.g., clicking sounds, no cranking, engine turning over but not starting), it's impossible to pinpoint the exact cause. Provide more details for a more accurate diagnosis.
