* Sensor Problems: Older cars, especially, are prone to sensor failures. Common culprits include:
* Oxygen Sensor (O2 Sensor): A faulty O2 sensor can disrupt the air/fuel mixture, leading to the check engine light.
* Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A malfunctioning MAF sensor can cause inaccurate fuel delivery.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's rotational speed. A failing CKP sensor can lead to misfires and the check engine light.
* Throttle Position Sensor (TPS): This sensor monitors the throttle position and can impact fuel delivery.
* Temperature Sensors: Incorrect readings from coolant temperature sensors or intake air temperature sensors can throw off the engine's calculations.
* Ignition System Issues:
* Spark Plugs or Wires: Worn-out spark plugs or damaged ignition wires can cause misfires, triggering the check engine light.
* Distributor Cap and Rotor (if applicable): Cracked or worn components in the distributor can interrupt the spark delivery.
* Exhaust System Leaks: A significant leak before the O2 sensor can confuse the system and illuminate the check engine light.
* Vacuum Leaks: Leaks in the vacuum system can disrupt engine operation and trigger the light.
* Catalytic Converter Issues: A failing catalytic converter can cause a variety of problems, including the check engine light.
How to proceed:
1. Get the Diagnostic Trouble Code (DTC): The most important step is to get the DTC. This is a code stored in the car's computer that indicates the specific problem. You can obtain this code using a dedicated OBD-I scanner (your car uses OBD-I, not OBD-II). Auto parts stores often offer free code reading services.
2. Check Obvious Things: Before taking it to a mechanic, you could visually inspect things like the spark plug wires and look for obvious damage.
3. Consult a Repair Manual: A repair manual specific to your 1994 Oldsmobile 88 Royale will provide diagrams and troubleshooting steps.
4. Professional Diagnosis: Once you have the DTC, take it to a qualified mechanic for a proper diagnosis and repair. They can interpret the code and pinpoint the exact cause of the problem much more efficiently than guessing.
Ignoring the check engine light can lead to further damage and more expensive repairs down the road. Getting it diagnosed promptly is the best course of action.
