Calculating Engine Frequency
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
Use the engine RPM where the vibration symptom occurs to determine engine frequency. Calculate engine frequency by dividing the engine RPM by 60 (the number of seconds in a minute). For example, if the corresponding engine RPM of a vibration concern on a vehicle is 2, 400 RPM, the resulting engine frequency is 40 Hz. Therefore, a 40 Hz vibration is a first order engine vibration. For purposes of vibration diagnosis, the engine also includes the torque converter and exhaust system.