Is a Long-Term Fuel Trim of -14.7 Rich or Lean?

[DelEmily]

Long-Term Fuel Trim of -14.7 indicates a rich condition. Below is relevant information: 1. Fuel Standards: Generally, the Long-Term Fuel Trim parameter ranges from -23% to 16%. A value of 0 indicates that no fuel compensation is needed to achieve the correct air-fuel mixture. A positive value means the injection system needs to inject additional fuel, indicating a lean mixture condition in the engine, which often results in difficult ignition. A negative value signifies that the injection system needs to reduce fuel delivery to correct an overly rich mixture. Therefore, a negative Long-Term Fuel Trim indicates that the vehicle's air-fuel mixture is too rich. 2. Long-Term Fuel Trim Standard: The standard range is typically ±5%. Exceeding this range usually indicates an engine malfunction. If the vehicle's fuel injectors are clogged, both the fuel injection volume and atomization effect will be poor, leading to a leaner combustible mixture concentration in the engine cylinders.