If the intake air temperature sensor fails or is disconnected in an F150, what is the effect on timing?

When the intake air temperature sensor fails or is disconnected, the engine control unit (ECU) does not receive accurate data about the temperature of the air entering the engine. As a result, the ECU defaults to a predetermined value or relies on basic maps stored in its memory for fuel calculations and timing adjustments.

In this scenario, timing does not change because the ECU cannot make informed adjustments based on temperature data. Instead, it operates within a conservative mode, maintaining a stable timing advance that is designed to keep the engine running safely. This default behavior prevents potential engine damage that might occur from inappropriate timing adjustments caused by erroneous or missing data.

In contrast, the other options imply that timing either advances, retards, or fluctuates based on the air temperature data. However, when the sensor is malfunctioning, the accuracy of the ECU's timing calculations becomes limited, leading to a consistent operation rather than variability.