Ignition Timing: Adjustments

Set timing at slow idle and Before Top Dead Center, unless otherwise specified.

Disconnect and plug distributor vacuum hose at distributor.

1981 4.3L (265), 4.9L (301), ground distributor bypass pigtail (blue connector).

1982-88 1.8L (112) FI, 2.0L (122) OHC, 2.5L (151) FI, 3.8L (229), ground diagnostic test terminal under dash.

1983-86 2.0L (122) FI, 2.8L (173) FI, 5.0L (305) CFI, disconnect bypass connector (tan/black wire).

1987-89 All FI W/distributors, disconnect timing bypass connector, single lead in every harness between distributor and ECM.

1981-89 Others, carburetted, disconnect 4-wire connector at distributor.

Timing MUST be set to specifications on emission label if different from setting listed. If "Check Engine" light comes on during procedure, remove ECM fuse to clear.