If the underhood emissions label states ignition timing is "non-adjustable," what is the correct response to timing specifications?

When the underhood emissions label specifies that ignition timing is "non-adjustable," it indicates that the vehicle's ignition timing is set by the manufacturer and should not be altered. In this context, the proper response regarding timing specifications is to enter the timing as "not applicable." This reflects the manufacturer's design and compliance with emissions standards, affirming that any attempt to adjust the timing could lead to non-compliance with emissions regulations.

Recording the timing as "not applicable" ensures that you accurately represent the vehicle's specifications as stated by the manufacturer, while also avoiding any miscommunication about the adjustments that are permissible. This practice aligns with the established guidelines for handling emission data, as there's no need for an adjustment on a system that is designed to remain fixed.