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Home >> Toyota >> 1997 >> T100 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - 2.7L >> Emission Systems & Sub-Systems >> Exhaust Gas RECIRCULATION (EGR) System Test
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Exhaust Gas RECIRCULATION (EGR) System Test

NOTE: EGR systems contain different components depending on application. See Fig 3. When testing EGR system and components, use proper illustration to determine component location.
NOTE: When performing EGR system test, it may be necessary to monitor engine RPM by using scan tool. For scan tool connections, see IDLE SPEED & MIXTURE in ADJUSTMENTS - 2.7L article.
  1. Ensure EGR vacuum modulator filter is clean and in good condition. Clean filter with compressed air (if necessary).
    NOTE: EGR vacuum modulator filter must be installed with coarse side facing upward, away from EGR vacuum modulator.
  2. Using "T" connector, install vacuum gauge in vacuum hose between EGR valve and EGR vacuum modulator. Start engine. Ensure engine runs idles smoothly to ensure proper seating of EGR valve.
    NOTE: The EGR system components must be checked with engine coolant temperature less than minimum temperature and engine at specified engine RPM.
  3. Operate engine with engine coolant temperature less than minimum temperature and at specified engine RPM. See EGR TESTING SPECIFICATIONS  table. No vacuum reading should be obtained. Check that EGR pipe is not hot.
  4. Remove "T" connector and small vacuum hose between port "Q" (single port) on EGR vacuum modulator and the EGR valve. See Fig 2. This 3-way connector and small vacuum hose goes from EGR valve and EGR vacuum modulator to the EGR Vacuum Switching Valve (VSV). Install plug in vacuum hose to EGR VSV.
  5. Connect vacuum hose from port "Q" on EGR vacuum modulator to directly to the EGR valve. See Fig 2. This will by-pass the EGR VSV.
  6. Operate engine at 3000 RPM. Ensure a low vacuum reading is now obtained with engine at 3000 RPM. Remove vacuum gauge and reconnect all vacuum hoses.
  7. To check EGR valve operation, remove and plug hose at EGR valve. Using vacuum pump, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall. If EGR system does not operate as described, each individual component should be tested.
EGR TESTING SPECIFICATIONS

Application Type Minimum Temperature Operating Temperature Engine RPM
2.7L 122°F (50°C) (1) 3000
(1) No specification is required for testing of EGR system.
Fig 1: Identifying Ports & Testing EGR Vacuum Modulator
G95A34439Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Removing 3-Way Connector & Installing Vacuum Hose On EGR Vacuum Modulator
G97E06382Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Identifying Emission System Components
G95J34461Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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