Install a vacuum gauge or water manometer in the intake air piping.

NOTE: The gauge adapter must be installed at a 90 degree angle to the air flow in a straight section of pipe, 127 mm [5.0 in], before the turbocharger compressor inlet.

Operate the engine at full throttle and maximum horsepower RPM with maximum load.

Record the reading on the gauge or manometer.

NOTE: Restriction must not exceed 635 mm H₂0 [25.0 in H₂0].

If the restriction exceeds specifications, replace or clean the air filter element. Refer to the OEM service manual.

Inspect the intake air piping for damage. Check for collapsed and dented piping or elbows and loose connections. Refer to the OEM service manual.

Remove the test equipment.