Ignition Timing: Adjustments
All except computer controlled eng., disconnect and plug distributor vacuum hose.
1981-84: 6.0L (368) FI eng., disconnect pink/black wire with connector from tan/black wire by distributor.
1981-86: 1.8L (112) 2V, 2.0L (122) 2V, 4.1L (252), 1986-90 5.0L (307): disconnect 4-wire connector at distributor.
1982-84: 4.1L (250), disconnect green reference signal connector.
1982-86: 2.0L (122) FI, 2.8L (173) FI, disconnect EST bypass connector (single connector tan/black wire).
1985-90: 4.1L (250), 4.5L (279), 5.7L (350), connect a jumper between terminals A & B of the diagnostic connector.
If "Check Engine" light comes on during this procedure, remove ECM fuse to clear.