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Home >> Chevrolet >> 1990 >> Forward Control 7.4 N, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments >> V6 Ignition Timing >> 3.1L (VIN D)
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3.1L (VIN D)

  1. Set parking brake, block drive wheels and place transmission in Neutral or Park. Warm engine to normal operating temperature. Turn A/C off (if equipped). Ensure SERVICE ENGINE SOON light is off.
  2. Disconnect and ground Tan/Black wire EST by-pass connector located in front of right strut tower. Connect timing light to No. 1 spark plug wire. Check timing and adjust if necessary. Refer to the V6 IGNITION TIMING SPECIFICATIONS  table.
  3. Disconnect ground from EST by-pass circuit and reconnect connector. Clear ECM trouble code.