1987 Pontiac Fiero Base, Standard, MG3FACTORY OEM SERVICE PROCEDURE

Positive Backpressure EGR Valve

A control valve, located in the EGR valve, acts as a vacuum regulator valve. The control valve controls the amount of vacuum to the EGR diaphragm chamber by bleeding vacuum to the atmosphere during certain operating conditions.

When the control valve receives a backpressure signal, through the hollow shaft of the EGR valve, pressure on the bottom of the control valve closes the control valve. When the control valve closes, the maximum vacuum signal is applied directly to the EGR valve allowing exhaust gas recirculation.

Factory Service Tools

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When to See a Mechanic

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

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

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