How to troubleshoot ignition problems on a 1969 AMC AMX?

When dealing with ignition problems on a 1969 AMC AMX, one might encounter symptoms such as difficulty starting the engine, poor engine performance, or the engine failing to start altogether. These issues can be traced back to various components within the ignition system, including the ignition coil, distributor, spark plugs, and ignition wiring. Identifying and resolving these problems is crucial for ensuring the smooth operation of your vehicle. Here is how to solve this issue.

Step 1: Inspect the Ignition Coil

The ignition coil is responsible for converting the battery's voltage to the higher voltage needed to create a spark at the spark plugs. The coil is typically a cylindrical component located near the distributor and spark plugs.

• Visual Identification: Look for a cylindrical component about the size of a soda can with wires connected to it.
• Testing: Use a multimeter to check the resistance of the ignition coil. Consult the vehicle’s service manual for the correct resistance values. If the reading falls outside the specified range, replace the ignition coil.

Step 2: Check the Distributor Cap and Rotor

The distributor cap and rotor are critical for directing the high-voltage current from the ignition coil to the spark plugs.

• Visual Identification: The distributor is usually round and located on the side of the engine. The cap covers this component and has wires coming out of it, leading to the spark plugs.
• Inspection: Remove the distributor cap by unscrewing the fastening screws and lifting it off. Check for corrosion, cracks, or carbon tracks inside the cap and on the rotor. If present, replace both the cap and rotor.

Step 3: Test Spark Plug Wires

Faulty spark plug wires can cause the engine to misfire or not start.

• Visual Identification: The spark plug wires are thick, insulated cables running from the distributor cap to each spark plug.
• Testing: With the engine off, remove one wire at a time and check for visible damage such as cracks or wear. You can also use a multimeter to measure the resistance. Replace any wires that appear damaged or have high resistance.

Step 4: Inspect the Spark Plugs

Spark plugs ignite the air-fuel mixture within the engine’s cylinders.

• Visual Identification: Spark plugs are located in the engine head and can be accessed by removing the spark plug wires and using a spark plug socket and wrench.
• Inspection: Remove each spark plug and inspect its condition. Look for signs of fouling (black carbon buildup), oil deposits, or melted electrodes. Clean or replace any spark plugs that show signs of damage or wear.

Step 5: Examine the Ignition Timing

Incorrect ignition timing can severely affect engine performance.

• Visual Identification: The timing marks are usually located on the engine’s harmonic balancer and the timing cover.
• Adjusting Timing: Use a timing light to check the ignition timing. Connect the timing light to the front spark plug wire, aim it at the timing marks, and compare the reading to the specifications in the service manual. Adjust the distributor’s position as needed to align the timing marks correctly.

Conclusion

By following these steps and thoroughly inspecting each component of the ignition system, you can effectively troubleshoot and resolve ignition issues in your 1969 AMC AMX. Regular maintenance and ensuring all components are in good working condition will help keep your vehicle running smoothly.