* Ignition Switch: Is the ignition switch itself functioning properly? A faulty switch won't send power to the rest of the ignition system. Try wiggling the key while in the "start" position to see if this is a loose connection issue.
* Ignition Control Module (ICM): The ICM is the "brain" of the ignition system in many vehicles, including some Reattas. It's responsible for timing the spark and sending signals to the coil. A faulty ICM is a common culprit for no spark. These often fail with age and heat.
* Crankshaft Position Sensor (CKP): This sensor tells the ICM the position of the crankshaft, which is essential for proper timing of the spark. A faulty CKP sensor will prevent spark.
* Cam Position Sensor (CMP): Some Reatta models may have a CMP sensor as well. It's function is similar to the CKP, but for the camshaft.
* Ignition Coil: The coil transforms low voltage battery power into the high voltage needed for the spark plugs. A bad coil won't produce the necessary voltage.
* Spark Plug Wires: Check the wires for cracks, fraying, or loose connections. A bad wire can prevent spark from reaching a specific cylinder or prevent any spark at all.
* Spark Plugs: Worn-out or fouled spark plugs will prevent proper ignition.
* Distributor (if applicable): Older Reattas may have a distributor; if so, check the cap, rotor, and pickup coil for wear or damage.
* Power Supply: Check the fuses and relays related to the ignition system. A blown fuse or failing relay will cut power to parts of the system.
How to Diagnose:
1. Start with the easy stuff: Check fuses, relays, and visually inspect the wires and plugs.
2. Use a multimeter: You'll need a multimeter to test the power supply to the ICM, coil, and sensors. You can also test the coil's output voltage. (Caution: High voltage in the ignition system can be dangerous. Be careful.)
3. Check for codes: Does the Buick Reatta have a diagnostic system (Check Engine light, etc.)? This can help pinpoint a specific problem area. A scanner might be necessary to read any stored trouble codes.
4. Consult a repair manual: A factory service manual for your specific year and model Reatta will be invaluable for diagrams and testing procedures.
Without more information on the specific symptoms, it's impossible to give a more precise answer. If you are not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. Working with high voltage can be dangerous.
