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Home >> Geo >> 1990 >> Tracker Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Emission Systems & Sub-Systems >> Exhaust Gas RECIRCULATION >> EGR System Check
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EGR System Check

CAUTION: Wear gloves if EGR valve is hot.
  1. With engine cool, grasp top of EGR valve and check for looseness. If looseness is felt, replace EGR valve. Warm engine to normal operating temperature. Place finger on bottom of EGR valve diaphragm. Start engine and increase engine speed. Note if EGR valve diaphragm moves.
  2. If diaphragm does not move, allow engine to idle. Disconnect vacuum hose from EGR valve and apply 10 in. Hg of vacuum. Vacuum should hold and engine should run rough or should stall. If vacuum does not hold, go to step 4).
  3. If engine did run rough or stall and EGR valve held vacuum, check components controlling vacuum supply to EGR valve, i.e. EGR modulator, EGR vacuum switching valve, vacuum supply and hoses. Also, check ECM control of ground circuit to EGR vacuum switching valve and verify EGR vacuum switching valve has power when ignition is on. For wire colors and ECM terminal identification, see appropriate wiring diagram in WIRING DIAGRAMS article.
  4. If EGR valve did not hold vacuum, replace EGR valve. If engine did not run rough or stall, remove EGR valve and check for plugged EGR valve or EGR passages in intake/exhaust system. Clean or replace as necessary.
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