What Causes a Ford Focus to Suddenly Fail to Start?
2 Answers
Reasons why a Ford Focus suddenly fails to start: Carbon deposits: Excessive carbon buildup in the idle motor, intake tract, intake valves, and combustion chamber. Excessive carbon deposits and dirt in the intake tract: Changes in the cross-sectional area of the air passage result in an overly rich or lean air-fuel mixture, causing abnormal combustion or engine shaking after starting, or even failure to start. Issues with the fuel injectors, such as leaks or excessive carbon deposits: Lead to a lean air-fuel mixture during startup, making it difficult to start. Faults in the carbon canister or carbon canister solenoid valve can also cause difficulty in starting. Additional information: From an electrical standpoint, it may be due to excessive spark plug electrode gap, decreased ignition coil energy, or short circuits or breaks in the cylinder wires. Engine mechanical faults are more complex, such as whether the valves are not sealing properly or whether there is excessive carbon buildup inside the engine. In winter, lower temperatures require more fuel for cold starts, and the presence of carbon deposits will significantly affect whether the cold start proceeds smoothly.
My old Ford Focus had the same issue not long ago. One morning when I was in a hurry to leave, it just wouldn't start no matter what, making me sweat with anxiety. Later inspection revealed severe oxidation on the battery terminals, covered with a white frost-like oxide layer. Cleaning it thoroughly with sandpaper and retightening solved the problem. This car is quite prone to this issue, especially with batteries over three years old. If there's no clicking sound when trying to start, it might be a starter circuit failure; if there's sound but the engine won't turn over, it's likely a dead battery. Once it was even more troublesome - the engine cranked loudly but wouldn't start, and it turned out to be a failed fuel pump, requiring a tow truck. I'd recommend Focus owners keep a set of emergency jumper cables in the glove box as a precaution.
