Ignition Timing: SC300

WARNING: This page is about a different car, the 1995 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.

Ensure engine is at normal operating temperature. Connect timing light magnetic pick-up to spark plug wire for cylinder No. 1. Connect tachometer test lead to terminal IG- of DLC No. 1, located on front end of air intake chamber. See Fig 1. Connect jumper wire between terminals TE1 and E1 of DLC No. 1.
Ensure idle speed is within specification. See IDLE SPEED SPECIFICATIONS table under IDLE SPEED & MIXTURE. Check base timing. See IGNITION TIMING table. If base timing is within specification, go to next step. If base timing is not within specification, adjust timing by rotating distributor, then go to next step.
Disconnect jumper wire from DLC No. 1. Check controlled timing. See IGNITION TIMING table. Ensure controlled timing is within specification. If controlled timing is not within specification, problem exists in engine control system.

IGNITION TIMING (Degrees BTDC @ RPM)

Application

⁽¹⁾ Base Timing

⁽²⁾ Controlled Timing

SC300

10 @ 650-750

7-19 @ 650-750

⁽¹⁾	Jumper wire connected between terminals TE1 and E1 of DLC No. 1. See Fig 1.

⁽²⁾	Jumper wire disconnected from DLC.

Fig 1: Identifying Terminals Of Data Link Connector (DLC) No. 1