* Distributor Cap and Rotor: These are prime suspects. Cracks, carbon tracking, or corrosion on the cap and rotor will impede the high voltage spark's ability to jump the gap. Inspect them carefully for any damage. Even a small imperfection can significantly weaken or eliminate the spark. Replacement is inexpensive and often solves the issue.
* Worn or Damaged Pickup Coil (Ignition Module): The pickup coil inside the distributor is responsible for sensing the crankshaft position and triggering the coil to fire. If it's worn, damaged, or misaligned, it won't send a strong enough signal, leading to a weak or absent spark at the distributor. This is a more involved repair, usually requiring distributor replacement or a separate module replacement depending on the design.
* Worn or Damaged Distributor Shaft: The distributor shaft can wear, causing the rotor to be misaligned or not spin smoothly. This can disrupt the timing and prevent a consistent spark.
* Ignition Control Module (ICM): While you're getting a *weak* spark at the coil, a faulty ICM might still be contributing. The ICM controls the timing and firing of the coil. A failing ICM might deliver insufficient voltage or improper timing signals to the coil.
* Wires and Connections: Check all wires leading to and from the coil and distributor for cracks, fraying, or corrosion. Loose connections or broken wires can severely restrict the current flow. Pay close attention to the high-voltage wire running from the coil to the distributor cap.
* Coil itself: Although you're getting *some* spark at the coil, it might be weak internally. While less likely given you have *some* spark, a failing coil is still a possibility.
* Cranking Speed: A weak battery or starter motor might not be turning the engine over fast enough to generate sufficient voltage for a good spark.
Troubleshooting Steps:
1. Visual Inspection: Start by thoroughly inspecting the distributor cap, rotor, and all wires and connections. Look for any obvious signs of damage.
2. Test the Coil: Use a multimeter to check the coil's primary and secondary resistances. Compare these readings to the specifications in your vehicle's repair manual. A weak or erratic reading may indicate a faulty coil.
3. Test the Pickup Coil (If Accessible): Accessing the pickup coil usually requires removing the distributor. Testing this component may require an oscilloscope or a specialized ignition testing tool.
4. Check for Spark at the Distributor: With a spark tester (or even a screwdriver with an insulated handle), carefully check for spark at each spark plug wire coming out of the distributor cap. This will help pinpoint if the problem is within the distributor itself or further down the line.
Important Note: Working with high voltage systems can be dangerous. If you are not comfortable working on your vehicle's ignition system, it's best to take it to a qualified mechanic. Incorrectly diagnosing or repairing the ignition system could lead to further damage or injury.
