What effect does installing a resistor in series with the intake air temperature (IAT) sensor have?

Installing a resistor in series with the intake air temperature (IAT) sensor will increase the signal voltage. The IAT sensor typically provides a variable resistance input to the Engine Control Unit (ECU), which monitors the temperature of the incoming air. By adding a resistor in series, the total resistance in the circuit changes, and this affects how the signal is interpreted by the ECU.

When the resistance is increased, it generally causes a change in the voltage level detected by the ECU. If a resistor is added correctly to the circuit, it can result in a shift that leads to a higher voltage reading being sent to the ECU, suggesting a higher air temperature than is actually present. Consequently, the ECU may interpret this increased signal voltage as a need to adjust fuel delivery, resulting in changes to fuel mixture and engine performance.

This explanation emphasizes the effect of the installation of a resistor in the context of how it interacts with the sensor's function and the resulting implications on engine management.