Heat-Related Possibilities:
* Faulty Ignition Module (again, but less likely): While less probable if it's a new module, a defective or poorly manufactured part could still be the culprit. Consider returning it for a replacement under warranty.
* Crankshaft Position Sensor (CKP Sensor): This sensor is crucial for the ignition system to know where the engine is in its cycle. They can fail when hot due to internal component degradation. When they fail, the engine won't start.
* Camshaft Position Sensor (CMP Sensor): Similar to the CKP sensor, a failing CMP sensor can prevent the engine from starting, especially when hot.
* Wiring Harness Issues: Heat can cause wires to short circuit or the insulation to melt, particularly near the engine where temperatures are high. Check for any obvious damage, melting, or loose connections in the wiring harness connected to the ignition module, CKP sensor, CMP sensor, and coil pack. Focus on areas exposed to engine heat.
* Coil Pack: While less likely to be heat-related directly (they usually fail completely rather than intermittently), a failing coil pack could behave strangely under heat stress.
* Poor Ground Connections: A poor ground connection can manifest in intermittent starting problems, particularly when components get hot and their resistance changes. Check the ground straps and connections on the engine and to the chassis for corrosion or looseness.
Troubleshooting Steps:
1. Check for Error Codes: If your Oldsmobile Achieva has an OBD-II port (less likely on a '94 model, but check under the dash), you can try a code reader to see if any diagnostic trouble codes (DTCs) are stored. This can point directly to a sensor or system problem. Even an older OBD-I system might have trouble codes visible in a certain sequence of indicator lamp flashes. Consult your owner's manual.
2. Test the Ignition Module (Again): Although less likely, carefully re-examine the new ignition module's installation and connections. Make sure it's securely mounted and the connections are clean and tight.
3. Check Sensors: If you have a multimeter, you can try testing the CKP and CMP sensors (refer to a repair manual for the correct test procedures and resistance values). These tests might require some mechanical aptitude.
4. Inspect Wiring: Thoroughly inspect all wiring related to the ignition system, especially near hot engine parts, for any signs of damage, melting, or loose connections. Repair or replace any damaged wiring.
5. Check Ground Connections: Clean and tighten all ground connections on the engine block and chassis. Use a wire brush to remove corrosion and make sure the connection is metal-to-metal.
6. Heat Soak Test: After the engine cools completely, try to start it. If it starts, let it run until it reaches normal operating temperature. If it stalls again once hot, this confirms the issue is heat-related.
Important Considerations:
* Repair Manual: A repair manual specific to your 1994 Oldsmobile Achieva is invaluable. It provides wiring diagrams, sensor locations, test procedures, and torque specifications.
* Professional Help: If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Improperly handling electrical systems can be dangerous.
By systematically checking these components and connections, you should be able to pinpoint the source of the problem. Remember to always prioritize safety when working on your car.
