1. What happened before it wouldn't restart?
* Did it just die while driving? This suggests a potential electrical problem (alternator, battery, ignition switch) or fuel delivery issue.
* Did it stall at idle? This could point to several problems, including a vacuum leak, fuel issue, or ignition problem.
* Did you turn it off and it wouldn't start again? This is less indicative of a specific problem and could be anything.
* Were there any warning lights on the dashboard before it died? (Check engine light, battery light, etc.) This is crucial information.
2. What are the symptoms when you try to restart it?
* Does it crank (turn over)?
* Yes: This means the battery and starter are likely okay. The problem is probably with fuel delivery, ignition, or the computer system.
* No: The problem could be the battery, starter, starter solenoid, ignition switch, or a related wiring issue. Check the battery connections for corrosion.
* Does it make any unusual noises when you try to crank it? (Clicking, grinding, etc.) This helps pinpoint the problem area.
* Does the engine try to turn over weakly? Low battery voltage.
* Does it crank normally but not start? Fuel, spark, or computer related.
3. What have you already tried?
* Checked the battery terminals for corrosion and tightness? Clean and tighten them.
* Checked the battery voltage? Should be around 12.6V when not running, and around 13.5-14.5V when running.
* Tried jump starting it? A successful jump start indicates a weak or dead battery. A failure suggests a more serious issue.
Possible Causes (Based on common S10 problems):
* Dead or weak battery: The most common cause. Check voltage and connections.
* Bad starter: If it doesn't crank, this is a strong suspect.
* Alternator: If the battery is weak, this could be the culprit. The alternator charges the battery while the engine is running.
* Fuel pump: It might not be delivering fuel. You might hear the pump prime when you turn the key to the "on" position (listen near the fuel tank).
* Ignition system problems: Spark plugs, wires, distributor (if equipped), ignition coil, crankshaft position sensor (CKP sensor).
* Fuel filter: A clogged fuel filter can restrict fuel flow.
* Computer issues: The engine control module (ECM) could be malfunctioning.
* Security system: If equipped, a faulty alarm or immobilizer could prevent starting.
* Cranking sensor Prevents engine from cranking.
Recommendation:
Without more detailed information, it's difficult to provide a definitive answer. Start by checking the battery and its connections. If you're not comfortable working on your vehicle's electrical system, take it to a mechanic. They have the tools and expertise to diagnose the problem accurately and safely. Providing them with the information above will significantly help them in their diagnosis.
