Ignition Timing
- Install timing light with an adapter between No. 1 spark plug and No. 1 spark plug wire or use an inductive pick-up. Do not puncture wire. On 4.3L engines, disconnect 1-wire (Tan with Black stripe) connector at distributor. On 2.8L engines, this wire connector is located in a taped section below heater case in passenger compartment.
NOTE:
Some GM engines use a magnetic timing probe hole for use with special electronic timing equipment. See equipment manufacture's directions for use of this equipment
- Check and adjust ignition timing with engine at normal operating temperature and transmission in "P" or "N" (auto. trans.) or Neutral (man. trans.) Reconnect 1-wire connector. Clear trouble code by removing ECM power fuse for 10 seconds.
IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)
| Application |
Man. Trans. |
Auto. Trans. |
| 2.8L |
10 @ Idle |
10 @ Idle |
| 4.3L |
0 @ Idle |
0 @ Idle |