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Home >> Mitsubishi >> 1985 >> Mirage Base >> Repair and Diagnosis >> Engine Performance >> System >> EGR System >> System Testing
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System Testing

  1. Check hoses for proper routing and condition. Cold start engine and run at idle. Observe the EGR valve for operation as engine speed is increased to 2500 RPM. There should be NO EGR operation after cold start. If the EGR valve operates, replace thermo valve.
  2. Warm engine until coolant reaches 185-194°F (85-90°C). Increase engine speed to 2500 RPM. Observe the EGR valve. The EGR valve should operate. If EGR is inoperative, check EGR valve and thermo valve. Replace as necessary.
  3. Detach hose (Green stripe) from thermo valve. Connect vacuum pump and apply vacuum. If no vacuum is available through thermo valve, valve is defective. Replace as necessary.
  4. Remove vacuum pump from thermo valve and reconnect hose (Green stripe) to thermo valve. Disconnect hose (Green stripe) from fitting at carburetor. Connect a vacuum pump to hose end.
  5. Apply 9.8 in. Hg of vacuum while opening sub EGR valve (pull valve open by hand). If idle speed becomes unstable the EGR valve is okay. If idle speed remains stable the EGR valve is NOT okay. Replace EGR valve as necessary.
  6. Remove the vacuum pump from hose end. Reconnect hose to carburetor. Disconnect the hose (Yellow stripe) from the EGR control valve. Connect vacuum pump to the fitting on the EGR control valve.
  7. Apply 5.9 in. Hg of vacuum while opening the sub EGR valve (pull valve open by hand). If idle speed becomes unstable the EGR valve is okay. If idle speed remains stable the EGR valve is NOT okay. Replace EGR valve as necessary.
  8. Remove vacuum pump from EGR control valve. Reconnect hose (Yellow stripe) to fitting of EGR control valve.
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