1. Ignition Coil: This transforms the low voltage from the battery into the high voltage needed for the spark plugs.
* Location: Usually mounted on the engine, often near the distributor (if equipped with one) or directly on top of the distributorless ignition system. It's a relatively large, cylindrical component.
* Symptoms: No spark at all, or very weak spark across all cylinders.
2. Ignition Control Module (ICM) or Electronic Control Unit (ECU): These are the "brains" of the ignition system. The ICM (in older systems) or ECU (more modern systems) sends the signal to the coil to fire.
* Location: The ICM is usually located near the distributor or coil, often mounted to the firewall or inner fender. The ECU is typically under the dashboard or in a less accessible location under the carpeting.
* Symptoms: Complete lack of spark, or intermittent sparking.
3. Distributor (if equipped): This distributes the high voltage from the coil to the correct spark plug at the precise time. Delta 88s of this era might have a distributor; some might have a distributorless ignition system.
* Location: On top of the engine. A spinning rotor inside distributes the spark.
* Symptoms: No spark, or misfiring in a specific cylinder order, or running on only some cylinders. Problems are often related to the rotor, cap, or internal components.
4. Crankshaft Position Sensor (CKP): This sensor tells the ICM/ECU the position of the crankshaft, allowing it to time the spark correctly.
* Location: Usually mounted on the engine block near the crankshaft pulley.
* Symptoms: No spark at all, as the computer doesn't know when to fire the coil.
5. Camshaft Position Sensor (CMP) (possibly): Some systems use this to further refine timing.
* Location: Usually near the camshaft.
* Symptoms: Similar to CKP sensor; lack of spark or misfiring.
6. Ignition Switch: This is what supplies power to the ignition system when the key is turned.
* Location: In the steering column.
* Symptoms: Could be a total lack of power to the ignition system, not just a spark problem. Test for voltage at the ignition coil or ICM.
7. Wiring: Broken, corroded, or loose wires anywhere in the ignition system can interrupt the flow of electricity.
* Location: Everywhere! Check all wires leading from the battery, ignition switch, ICM/ECU, coil, distributor (if equipped), and spark plugs.
Troubleshooting Steps (in order):
1. Check for power at the coil: Use a multimeter to see if the coil is receiving 12V from the ignition switch when the key is turned to the "start" position. This is your first, critical check. No power here points to the ignition switch, wiring, or perhaps a faulty ignition relay.
2. Check the coil for continuity: With the multimeter, check the coil's primary and secondary windings for continuity (resistance). A failed coil will show an open circuit (infinite resistance).
3. Inspect the distributor (if applicable): Check the rotor, cap, and wires for damage or corrosion.
4. Check the CKP sensor: Testing this often requires a scan tool or multimeter and understanding the sensor's resistance.
5. Check the ICM/ECU: This often requires a scan tool to test for proper operation. A failing ICM is often a common cause in older vehicles.
Important Notes:
* Safety First: Disconnect the negative battery cable before working on any electrical components.
* Professional Help: If you're not comfortable working with automotive electrical systems, it's best to take your car to a qualified mechanic. Troubleshooting ignition problems can be challenging, and improper diagnosis can lead to further damage.
* Year-Specific Differences: The exact location and configuration of these components may vary slightly depending on the specific model and trim level of your 1990 Oldsmobile Delta 88. Consult a repair manual specific to your vehicle for detailed diagrams and specifications.
By systematically checking these components, you should be able to pinpoint the cause of your no-spark issue. Remember to always prioritize safety when working on your vehicle.
