Deceleration System: Testing

1982 Peugeot 505 STI, 2.0L Eng VIN 1, Automatic TransSECTION Testing
  1. With engine temperature below 104°F (40°C), disconnect the top wire from the thermocontact. Start engine and accelerate to 1800 RPM or more.
  2. Quickly release throttle. If operation of deceleration valve can be heard, system is good. Reconnect wire.
  3. If deceleration valve could not be heard, disconnect deceleration valve connector. Connect test lamp to connector.
  4. Again accelerate to 1800 RPM or more and quickly release throttle. If test lamp comes on then goes off, check vacuum hose routing. If connections are good, replace deceleration valve.
  5. If test lamp does not come on, check electrical connections, 2-speed relay and adjustment of microswitch. See ADJUSTMENTS . If all are okay, replace deceleration relay.
RENDER: 1.0x

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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.