GS400, LS400 & SC400
- Warm engine to normal operating temperature. Turn ignition off. ON LS400 & SC400, remove battery cover. Remove air cleaner and air intake duct. On all models, remove engine cover. Connect timing light to Yellow lead wire at ignition coil connector for cylinder No. 1.
- Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Scan tool is used to read engine RPM. Apply parking brake. Ensure all accessories are off. Place transmission Neutral. Start engine and maintain engine speed at 2500 RPM for 90 seconds and then allow engine to idle. On GS400, ensure cooling fan is off. On all models, ensure idle speed is 700-800 RPM.
- Install Jumper Wire (SST 09843-18020) between terminals TC and E1 of DLC No. 1. See Figure. Connector is located near air intake chamber. Check base timing. See IGNITION TIMING table.
- If base timing is correct, procedure is complete. If base timing is not correct, check for one or more of the following conditions. Repair as necessary.
- Improper operation of air intake system.
- Throttle valve is being prevented from fully closing.
- Throttle position sensor is misadjusted. See THROTTLE POSITION (TP) SENSOR .
- Valve timing is incorrect (timing belt is not correctly installed).
IGNITION TIMING (Degrees BTDC @ RPM)
| Application |
Base Timing |
Controlled Timing |
| ES300 |
8-12 @ 650-750 |
7-24 @ 650-750 |
| GS300 & SC300 |
8-12 @ 650-750 |
6-16 @ 650-750 |
| GS400, LS400 & SC400 |
8-12 @ 650-750 |
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