Ignition System Problems:
* Distributor cap and rotor: These are common wear items. Cracks, corrosion, or worn contacts can prevent spark delivery.
* Ignition coil: A faulty coil won't produce the necessary high voltage for sparking. It might be cracked, shorted, or simply worn out.
* Ignition wires (spark plug wires): Cracked or corroded wires can create arcing and misfires, or completely prevent spark reaching the plugs. Look for visible damage or signs of arcing.
* Spark plugs: Worn, fouled, or damaged spark plugs are a frequent culprit. They might be excessively worn, covered in carbon buildup, or simply broken.
* Ignition switch: A failing ignition switch might not be sending power to the rest of the ignition system.
* Ignition control module (ICM) (if equipped): This electronic component controls the ignition timing and might fail, preventing spark. More likely on later-model 79s or those with electronic ignition.
* Pick-up coil (in the distributor): This sends the signal to the ICM or points/condenser (depending on the ignition system) to trigger the spark. A bad one will prevent firing.
* Points and condenser (if equipped): These are older ignition components, less common on a '79 but still possible. Worn points won't make good contact, and a bad condenser can prevent spark.
Fuel System Problems:
* Fuel pump: A faulty fuel pump won't deliver fuel to the carburetor or fuel injectors. You might hear a weak whirring sound, or nothing at all.
* Fuel filter: A clogged fuel filter restricts fuel flow, preventing sufficient fuel reaching the engine.
* Carburetor (if equipped): A problem with the carburetor (clogged jets, stuck float, etc.) can prevent fuel delivery.
* Fuel lines: Cracked or blocked fuel lines can interrupt fuel flow.
Other Potential Causes:
* Crankshaft position sensor (CKP sensor) (if equipped): This sensor tells the computer when the engine is turning. A bad sensor will prevent ignition.
* Battery and cables: A weak battery or loose/corroded cables won't provide enough power to the ignition system.
* Distributor timing: If the distributor is significantly out of time, the engine may not fire reliably or at all.
Troubleshooting Steps:
1. Check for spark: Remove a spark plug, ground it to the engine block, and crank the engine. You should see a strong spark. If not, the problem is in the ignition system.
2. Check for fuel: Inspect the fuel lines for leaks or blockages. Check the fuel pressure if possible.
3. Check the basics: Ensure the battery is charged and the terminals are clean and tight.
4. Listen for the fuel pump: Turn the key to the "on" position (without cranking). You should hear the fuel pump run for a few seconds.
If you're not comfortable working on your car, it's best to take it to a mechanic for diagnosis and repair. Many of these components interact, and determining the exact cause requires systematic testing.
