Transmission Controlled Spark System: Testing and Inspection

1982 Chevrolet Camaro V8-305 5.0L VIN H 4-bblSECTION Testing and Inspection
NOTE: To test the SCS system, leave the distributor vacuum hose connected, ensure that engine coolant temperature is between 95° and 230° F and proceed as follows:

1. Raise the rear wheels.
2. Start engine and shift into Drive.
3. Accelerate engine while observing timing mark on harmonic balancer.
4. Timing should advance when vehicle speed exceeds 35 mph.

No Vacuum Advance At Calibration Speed

NOTE: If vacuum advance does not occur at speeds over 35 mph, check for:

1. Reversed vacuum lines at vacuum solenoid valve.
2. Foreign matter in vacuum solenoid valve.
3. Disconnected or broken distributor vacuum line.
4. Defective vacuum solenoid valve.
5. Shorted speed sensor switch or wire.


Full Vacuum Advance At All Speeds

NOTE: If full vacuum advance occurs at all vehicle speeds, check system for:

1. Blown fuse.
2. Disconnected wire at vacuum solenoid valve.
3. Disconnected wire at speed control switch or faulty switch.
4. Faulty temperature switch.

RENDER: 1.0x

NO RELATED

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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.