1987 Pontiac Fiero Base, Standard, MG3FACTORY OEM SERVICE PROCEDURE

Ported EGR Valve

  1. Turn ignition off. Disconnect EGR vacuum hose at vacuum signal tube. Connect a hand-held vacuum pump to vacuum signal tube and apply 10 in. Hg. EGR diaphragm plate should move up and remain up for at least 20 seconds.
  2. If diaphragm moves up and holds for 20 seconds, diaphragm is operating properly. If diaphragm does not hold vacuum, replace EGR valve. Place transmission in Park or Neutral and connect vacuum pump to EGR valve.
  3. With engine running at normal operating temperature, push up on diaphragm. Engine RPM should decrease. If RPM decreases, EGR valve is functioning properly. If engine RPM does not decrease, replace EGR valve. If further testing is required, see the appropriate COMPONENT TESTING article in the EMISSION section.
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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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