* Fuel injectors: A clogged or sticking fuel injector could be delivering too much fuel initially, leading to a rich mixture, causing sputtering and the fuel smell. This is especially likely if the problem improves after the engine warms up.
* Fuel pressure regulator: A faulty fuel pressure regulator might allow excessive fuel pressure when the engine is cold, leading to a similar rich mixture issue.
* Mass airflow sensor (MAF sensor): A malfunctioning MAF sensor can provide incorrect air/fuel mixture readings to the engine's computer (ECM). An inaccurate reading during cold start might lead to a too-rich mixture.
* Throttle position sensor (TPS): Similar to the MAF sensor, a bad TPS can send inaccurate information to the ECM, affecting the fuel delivery calculation.
* Cold start injector: Some cars have a dedicated cold start injector that squirts extra fuel during cold starts to aid ignition. A faulty or leaking cold start injector would cause excessive fuel.
* Ignition system: While less likely to directly cause a strong fuel smell, a weak spark (worn spark plugs, faulty ignition coil, bad distributor cap or rotor) could lead to incomplete combustion. Unburnt fuel would then be expelled, causing the smell. The sputtering supports this possibility as well.
* Engine coolant temperature sensor (ECT sensor): The ECM relies on the ECT sensor to determine how rich the mixture should be. A faulty ECT sensor providing incorrect readings (especially a falsely low temperature) could make the ECM add too much fuel during cold starts.
Troubleshooting Steps:
1. Check for any diagnostic trouble codes (DTCs): Use an OBD-I scanner (appropriate for your 1994 model) to see if any codes are stored in the ECM's memory. These codes can pinpoint the problem.
2. Inspect the fuel injectors: Visually check the injectors for leaks or signs of damage. A more thorough inspection would require specialized equipment.
3. Check the spark plugs and wires: Inspect the spark plugs for fouling, wear, or damage. Check the spark plug wires for cracks or damage.
4. Check the fuel pressure: This requires a fuel pressure gauge and potentially specialized tools. Compare the reading to the manufacturer's specifications.
5. Inspect the MAF sensor and TPS: Look for any visible damage or contamination. Cleaning the MAF sensor (carefully, following instructions) might resolve the issue if it's dirty.
6. Check the engine coolant temperature sensor: This can be tested with a multimeter.
Because several components could be the cause, systematic troubleshooting with diagnostic tools and tests is necessary. If you're not comfortable performing these checks yourself, taking it to a qualified mechanic is recommended. Ignoring the problem could lead to more serious engine damage.
