* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position, crucial for timing the spark. A faulty CKP sensor prevents the computer from sending the signal to fire the spark. This is a very common cause of a no-spark condition.
* Distributor (if equipped): While less common in 1989, some 318s might still have a distributor. Issues could include:
* Ignition coil: The coil is responsible for boosting the voltage to create the spark. A bad coil is a frequent suspect.
* Distributor cap and rotor: These wear out over time and can cause poor or no spark. Check for cracks, corrosion, or excessive wear.
* Pick-up coil (inside the distributor): This senses the rotor position and sends the signal to the ignition control module.
* Ignition Control Module (ICM): This is the "brain" of the ignition system in many 1989 vehicles. It receives signals from the CKP sensor and other inputs and triggers the ignition coil. A faulty ICM will result in no spark.
* Ignition Switch: A failing ignition switch might not be supplying power to the necessary components of the ignition system.
* Wiring: Check all wiring related to the ignition system for broken wires, corroded connections, or short circuits. This includes the wires to the CKP sensor, coil, ICM, and distributor (if applicable). A visual inspection is a good starting point, followed by testing with a multimeter.
* Computer (PCM/ECM): While less likely to be the primary cause of a complete no-spark condition, a faulty PCM/ECM could prevent the ignition system from functioning properly. This is usually diagnosed last after other components have been checked.
* Fuses and Relays: Make sure all relevant fuses and relays are intact and functioning correctly.
Troubleshooting Steps:
1. Check for power at the coil: Use a multimeter to test for battery voltage at the coil's positive terminal when the key is turned to the "on" position. No voltage indicates a problem upstream (ignition switch, wiring, etc.).
2. Inspect the distributor (if applicable): Check the cap, rotor, and wires for any obvious signs of damage.
3. Check the CKP sensor: Test the CKP sensor for continuity and signal using a multimeter. You'll likely need a wiring diagram or a service manual for your specific year and model to locate the sensor and its wiring.
4. Test the ignition coil: A simple resistance test with a multimeter can determine if the coil is faulty.
5. Test the ICM (if applicable): This usually requires a specific tool or diagnostic scan tool.
Important Note: Working on automotive electrical systems requires some basic knowledge of automotive electricity and the use of a multimeter. If you are not comfortable working with electricity, it is best to take your vehicle to a qualified mechanic for diagnosis and repair. Incorrectly testing or repairing the ignition system can lead to damage or injury.
