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Home >> Jeep >> 1984 >> Pickup J20 >> Repair and Diagnosis >> Engine Performance >> System >> EGR System >> Testing >> EGR Valve >> Valve Closing Test
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Valve Closing Test

  1. With engine at normal operating temperature and at curb idle, manually depress EGR valve diaphragm. This should cause immediate engine speed drop, indicating that EGR valve had been properly cutting off exhaust gas flow at idle.
  2. If there is no change in RPM and engine is idling properly, exhaust gases are not reaching combustion chamber. There is probably a plugged passage between EGR valve and intake manifold.
  3. If engine idles poorly and RPM is not greatly affected by moving diaphragm, EGR valve is not closing off exhaust gas flow. Defective hoses, hose routing, or EGR valve is problem.
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