What Causes Intermittent Car Starting Difficulties?
1 Answers
Common causes of difficult car ignition include: 1. Incorrect fuel-air mixture ratio. 2. Overly rich combustible mixture. 3. No spark or weak spark from spark plugs. 4. Insufficient battery charge. 5. Incorrect ignition timing. 6. Insufficient cylinder compression pressure. 7. Excessive carbon buildup or blockage in the exhaust port and muffler. To troubleshoot starting difficulties, follow these steps sequentially: 1. Press the horn button to assess battery charge level by sound intensity. If weak, check electrolyte levels and inspect for damage to battery casing or plates. 2. Examine spark plugs to determine whether the issue lies in the ignition system (weak/no spark) or fuel system. Ignition system faults may include: dirty spark plugs, broken high-tension wires, damaged capacitors/diodes/transistor circuits, unopened/break in ignition switch/main switch, or incorrect breaker point gap/surface irregularity. 3. Remove spark plugs and crank the engine. Analyze exhaust gas moisture/odor to identify fuel system issues or ignition timing problems. Dry spark plugs with odorless exhaust indicate no mixture entering cylinders - check fuel tank valve, fuel lines, and carburetor for blockages. Gasoline-smelling exhaust with no visible oil droplets on white paper near spark plug holes suggests overly lean mixture. Wet spark plugs indicate overly rich mixture. 4. Remove engine cover to verify ignition timing. Adjust breaker if incorrect; clean breaker if timing is correct. 5. Use a compression gauge: Pressure below 6.10 Pascals indicates internal mechanical faults (damaged cylinder/crankcase gaskets, leaking crankcase seals, or loose bolts). Pressure above 6.10 Pascals requires exhaust system inspection. Without a gauge: Remove spark plug, finger-test compression by cranking engine. Strong pressure pulses with "popping" sounds indicate good compression/crankcase sealing; weak/no pulses with difficult cranking suggest crankcase or piston ring leakage. 6. Remove muffler to check for carbon blockage. 7. Test battery voltage and overall condition.
