* Fuel System Issues:
* Fuel pump: The most likely suspect. When the engine sits, the fuel pressure in the lines can bleed off. A weak or failing fuel pump might not build pressure quickly enough for a cold start. Listen carefully near the fuel tank (you might need to have someone crank the engine while you listen) for a humming sound when the key is first turned to the "on" position (but not cranking). A weak hum or no hum indicates a potential fuel pump problem.
* Fuel pressure regulator: This regulates fuel pressure in the system. A faulty regulator could allow pressure to leak off overnight.
* Clogged fuel filter: Restricts fuel flow, especially problematic when the fuel is cold and thicker.
* Ignition System Issues:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A failing CKP sensor can cause hard starting, especially when cold.
* Ignition coil: Could be weak or failing, leading to poor spark when cold.
* Distributor cap and rotor (if applicable): Check for cracks, corrosion, or worn contacts. These are less likely on a '93 but still possible.
* Ignition module: Controls the ignition coil. A failing module can cause intermittent starting issues.
* Other Possibilities:
* Intake Air Leak: A vacuum leak will make it harder to start, especially cold.
* Battery: A weak battery might have enough power to start a warm engine but not a cold one. Have the battery load tested.
* Starter: While less likely if it cranks over, a weak starter motor could struggle with cold, thicker oil.
Troubleshooting Steps:
1. Check the battery: Have it load tested at an auto parts store. A weak battery is a common cause of hard starting.
2. Listen for the fuel pump: As mentioned above, listen for the hum when the key is turned to "on".
3. Check fuel pressure: This requires a fuel pressure gauge and adapter. You'll need to connect the gauge to the fuel system and check the pressure when the key is turned on and the engine is cranking. Compare this to the factory specifications for your vehicle.
4. Inspect the ignition system: Look for cracks in the distributor cap and rotor (if equipped), corrosion on the spark plug wires, and any signs of damage to the ignition coil.
5. Check for vacuum leaks: Visually inspect all vacuum lines and connections for cracks or loose fittings. Use a propane torch (carefully!) to check for leaks near the intake manifold. A change in idle speed indicates a leak.
6. Have a mechanic check the CKP sensor: This often requires a scan tool to properly diagnose.
Important Note: Starting fluid (ether) can be dangerous and can damage your engine. Avoid using it unless you are absolutely sure you know what you are doing and it's a last resort.
Start with the simpler checks (battery, fuel pump sound, visual inspection) and work your way to the more involved diagnostics (fuel pressure test, CKP sensor check). If you are not comfortable performing these checks yourself, take it to a qualified mechanic. Providing them with the information you've gathered will help them diagnose the problem more efficiently.
