Pinpoint Test F: Drumming Noise

F1 CHECK THE EXHAUST SYSTEM
- Key in START position.
- Increase the engine rpm until the noise is the loudest. Note the engine rpm.
- Key in OFF position.
- Add approximately 9 kg (20 lb) of weight to the exhaust system. First place the weight at the tail pipe and test, then at the front pipe.
  
  Fig 1: Pinpoint Test F: Drumming Noise
  Courtesy of FORD MOTOR CO.
- Key in START position.
- Increase the engine rpm and listen for the drumming noise. Note the engine rpm if the noise occurs.
- Key in OFF position.
- Using a vibration analyzer (VA), determine the amount of vibration that occurs with the drumming noise.
- Is the noise/vibration reduced or eliminated, or does the noise/vibration occur at a different rpm?
1. Yes: Carry out EXHAUST SYSTEM NEUTRALIZING . TEST the system for normal operation.
2. No: GO to F2.
F2 POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING
- Carry out POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING . Test the system for normal operation.
- Is the noise reduced or eliminated?
1. Yes: Vehicle OK. TEST the system for normal operation.
2. No: CONDUCT diagnosis of other suspect components.