1987 Mitsubishi Starion ESI-RFACTORY OEM SERVICE PROCEDURE

CORDIA & TREDIA

  1. Check hoses for proper routing and condition. Cold start engine and run at idle. Observe EGR valve for operation as speed is increased to 2500 RPM. There should be NO EGR operation after cold start. If EGR valve operates, replace thermo valve.
  2. Warm engine until coolant reaches 185-205°F (85-95°C). Increase engine speed to 2500 RPM. Observe operation of EGR valve. If EGR is inoperative, check EGR valve and thermo valve and replace as necessary.
  3. Detach Green-striped hose from thermo valve. Connect vacuum to thermo valve and attempt to create vacuum. If no vacuum can be created, valve is defective. Replace as necessary.
  4. Remove vacuum pump from the thermo valve and reconnect Green-striped hose. Disconnect Green-striped hose from EGR control valve. Connect vacuum pump to nipple and apply 9.5 in. Hg of vacuum.
  5. If idle speed becomes unstable, EGR control valve is okay. If idle speed remains stable, EGR control valve is NOT okay. Replace valve as necessary. Remove vacuum pump from nipple and reconnect Green-striped hose to EGR control valve.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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