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Home >> Toyota >> 1991 >> Supra 7M-GE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Emission Systems & Sub-Systems >> Exhaust Gas RECIRCULATION >> System Test
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System Test

  1. Ensure modulator filter is clean and in good condition prior to performing test. Clean filter with compressed air. Disconnect vacuum hose from EGR valve.
  2. Using a "T" connector, connect a vacuum gauge in EGR valve vacuum line. Ensure engine starts and runs smoothly at idle. This ensures proper seating of EGR valve.
  3. The Vacuum Switching Valve (VSV) and EGR modulator can be checked with engine coolant temperature less than 135°F (57°C) at 2500 RPM.
  4. Operate engine with engine coolant temperature less than 135°F (57°C) at 2500 RPM. No vacuum reading should be obtained when operated with engine coolant temperature less than minimum temperature.
  5. Operate engine at normal operating temperature at 2500 RPM. A vacuum reading of 2.8 in. Hg should be obtained.
  6. On Non-Turbo, disconnect hose from the "R" port of EGR vacuum modulator. See Figure.
  7. Using additional hose, connect "R" port directly to intake manifold. High vacuum reading should be obtained at 2500 RPM.
    NOTE: Engine should misfire due to large amounts of exhaust gas being injected into intake manifold.
  8. To check EGR valve, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall. If system did not operate as described, each component should be tested.
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