Car won't start after spark plug change
A no-start condition immediately after installing new spark plugs usually points to something disturbed during the repair rather than a sudden major failure. The ignition system is highly sensitive to firing order, connector seating, and small assembly mistakes. Because the engine ran recently and the work area was limited, owners should inspect the specific components touched during the plug swap. Cranking behavior, connector fit, and recent wiring movement offer the fastest clues. A methodical inspection of those areas often reveals a simple installation error before deeper engine diagnosis is needed.
Direct answer
When a vehicle cranks but will not fire after new plugs are fitted, the most common cause is a disturbance in the secondary ignition path. Plug wires or coil connectors may be crossed, not fully seated onto the plug terminal, or damaged internally when pulled free. A boot that feels connected can still sit too high to make contact. Confirming that each wire reaches the correct cylinder and snaps firmly onto the plug is therefore the first practical step because the repair area is the only thing that changed.
Another direct explanation is that the no-start came from a low battery state of charge after the hood was open with interior lights or a door left ajar. Slow cranking speed can sound normal while still failing to generate enough coil energy for a reliable spark. Listening for a weak, labored crank instead of a crisp spin helps separate an electrical supply problem from a fuel delivery or spark routing fault. If cranking speed is strong, the focus should shift back to the connectors and ignition components handled during the job.