Mike's Workshop Manuals: Service manuals for every vehicle
Home >> GMC >> 1992 >> Forward Control 7.4 N >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments >> Ignition Timing (Gasoline) >> V6 Ignition Timing >> All Models (Except 3.8L VIN L)

All Models (Except 3.8L VIN L)

  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 Tan/Black Electronic Spark Timing (EST) by-pass connector wire. On 4.3L, by-pass connector is on wiring harness conduit near distributor. On other models, by-pass connector is located near heater housing in passenger compartment. On all models, 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 V6 IGNITION TIMING . Reconnect EST by-pass connector, and clear ECM trouble code.
V6 IGNITION TIMING (DEGREES BTDC @ RPM)

Application Man. Trans. Auto. Trans.
2.8L (VIN R) 10 @ Idle 10 @ Idle
3.1L (VIN D) 10 @ Idle 10 @ Idle
3.8L (VIN L) (1) (1)
4.3L (VIN W & Z) 0 @ Idle 0 @ Idle
(1) Ignition timing is not adjustable (DIS).