INSPECTION
Check TP sensor resistance. See THROTTLE POSITION (TP) SENSOR under FUEL SYSTEM in SPECIFICATIONS article. If resistance is not as specified, adjust TP sensor.
- Disconnect TP sensor connector. Loosen TP sensor mounting screws. Apply vacuum to throttle opener to allow throttle to fully seat. Insert specified feeler gauge between throttle stop screw and throttle lever. See TP SENSOR ADJUSTMENT table.
- Connect ohmmeter between terminals IDL (or IDL1) and E2 of TP sensor connector. (Scheme 1) Rotate TP sensor counterclockwise until there is no continuity, then rotate it clockwise until there is continuity. Tighten TP sensor mounting screws. Inspect TP sensor again.
| Application | Feeler Gauge Thickness |
|---|---|
| LS400 | .016" (.41 mm) |
TP SENSOR ADJUSTMENT
Scheme 1
Check sub-TP sensor resistance. See SUB-THROTTLE POSITION (SUB-TP) SENSOR under FUEL SYSTEM in SPECIFICATIONS article. If resistance is not as specified, adjust sub-TP sensor.
- Disconnect sub-TP sensor connector. Loosen sub-TP sensor mounting screws. Remove sub-throttle actuator. Ensure sub-throttle valve is fully closed and sub-throttle valve gear is touching stop screw. Insert feeler gauge between gear and stop screw. See SUB-TP SENSOR ADJUSTMENT table.
- Connect ohmmeter between terminals IDL2 and E2 of sub-TP sensor connector. (Scheme 1) Rotate sub-TP sensor counterclockwise until there is no continuity, then rotate it clockwise until there is continuity. Tighten sub-TP sensor mounting screws. Inspect sub-TP sensor again. SUB-TP SENSOR ADJUSTMENT Application Feeler Gauge Thickness LS400.012" (.30 mm)
- Warm engine. Ensure idle speed is 650-750 RPM. Remove cap, filter and separator from end of dashpot. (Scheme 2) Start engine and raise engine speed to 4000 RPM. Use finger to cover hole inside area where separator is normally installed in dashpot. Release throttle valve. This will fully extend dashpot rod. Check engine speed (ensure cooling fan is not running).
- If engine speed (dashpot set speed) is not 2500 RPM, rotate dashpot adjusting screw as necessary. When installing separator, filter and cap, install filter with coarse side facing away from dashpot.
