What this test proves

Locate unmetered-air leaks in the selected intake section with regulated smoke.

Tools

  • Automotive smoke machine approved for the application
  • Proper adapters and blanking plugs
  • Intake/PCV diagram

Preparation and precautions

  • Engine off; follow temperature and machine-fluid requirements.
  • Isolate only the specified boundaries and protect sensors. Do not use unregulated shop air or a flammable improvised smoke source.

Connections

  • Connect at the prescribed intake port and seal the required openings without overpressurizing PCV, EVAP or other connected systems.

Equipment settings

  • Use the machine/OEM pressure and flow limit for the intake. An EVAP or boost procedure may require different limits.

Test sequence

  1. Define the section under test.
  2. Introduce smoke at controlled pressure.
  3. Inspect hoses, joints, manifold seals and approved connected paths.
  4. Distinguish intended vents from leaks.
  5. Remove all plugs, restore routing and verify operation.

Expected signal / readings

Unintended smoke escape identifies a possible leak path within the tested boundaries.

Interpreting results

  • Normal vents or open valves may release smoke without a defect.
  • A static test may miss a heat- or vacuum-dependent opening.

Common mistakes

  • Leaving a blanking plug installed
  • Overpressurizing connected components
  • Assuming every smoke outlet is a fault