Ignition Timing

CAUTION: Some tachometers may not be compatible with ignition system. Consult tachometer manufacturer before connecting tachometer to system. To avoid possible damage to ignitor and/or coil, DO NOT allow tachometer terminal to become grounded.

Ensure engine is at normal operating temperature. Connect timing light to engine. Connect tachometer to proper location. See Fig 1-Fig 3 .
Install jumper wire between proper terminals of engine check connector. See Fig 4-Fig 6 . Ensure idle speed is within specification. See appropriate IDLE SPEED SPECIFICATIONS table under IDLE SPEED & MIXTURE. Ensure base timing is within specification. Also, see the IGNITION TIMING table.
NOTE: Timing marks are on front cover on all models except Land Cruiser. On Land Cruiser, timing mark on flywheel must be aligned with pointer positioned above starter motor. See Fig 7.
On Supra turbo with Distributorless Ignition System (DIS), adjust timing by turning cam position sensor. On all other models, adjust timing by turning distributor.
Remove jumper wire from engine check connector and ensure advance timing is within specification. See IGNITION TIMING table. Tighten distributor hold-down bolt or cam position sensor bolt (Supra turbo). See TORQUE SPECIFICATIONS .