1987 Pontiac Fiero Base, Standard, MG3FACTORY OEM SERVICE PROCEDURE

Reference Ground

The EST system is grounded through the DIS ignition module to ensure that ground circuit does not have an excessive voltage drop between ignition module and the ECM. An excessive voltage drop in system could affect engine performance.

Fig 1: 2.0L Direct Ignition System (DIS) Components
G7832
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:

  • • 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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