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Home >> GMC >> 1997 >> Forward Control 7.4 J >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Controls - Adjustments - 7.4L) >> Ignition Timing
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Ignition Timing

WARNING: This page does not describe the selected car, but rather 16 other vehicles, including the 1995 GMC Vandura Special, 1995 GMC Vandura, 1995 GMC Suburban, 1995 GMC Rally Camper Special, and 1995 GMC Rally. However, it is still accessible from the selected car via links, so may be relevant.
  1. Set parking brake. Block drive wheels. Place transmission in Neutral or Park. Warm engine to operating temperature. Turn A/C off (if equipped). Ensure Malfunction Indicator Light (MIL) is not on.
  2. Disconnect Tan/Black Electronic Spark Timing (EST) by-pass connector wire located near distributor, or in cab under glove box. DO NOT disconnect 4-wire connector at distributor.
  3. Connect timing light to No. 1 spark plug wire. Check timing and adjust if necessary. See IGNITION TIMING . Reconnect EST by-pass connector. Clear DTC.
IGNITION TIMING (DEGREES BTDC @ RPM)

Application Man. Trans. Auto. Trans.
7.4L (VIN N) 4 @ Idle 4 @ Idle
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