Idle Speed/Throttle Actuator - Mechanical: Testing and Inspection

1. Remove air cleaner. Start the engine and warm-up to normal operating temperature.
2. Confirm that choke opener and EGR system are OFF, by disconnecting vacuum hose from the TVSV port M and plugging the hose. Fig. 27

Fig. 27 TVSV Vacuum Hoses:

3. Disconnect the vacuum hose from the throttle positioner.
4. Set the TP setting speed by turning the adjusting screw. Make adjustments with the engine cooling fan OFF and transmission in neutral.

TP Setting Speed: 900 rpm

Fig. 29a Testing VTV Air Flow:

5. Reconnect vacuum hose to the throttle positioner and check that the engine returns to idle speed within 2 - 6 seconds.
6. If not as specified, continue with testing procedure.
7. Turn engine OFF and reconnect the TVSV vacuum hose.
8. Remove the vacuum transmitting valve (VTV) from the engine.
9. Check that air passes without resistance from pipe B to pipe A. Fig. 29a
10. Check that air does NOT pass from pipe A to pipe B.
11. If not as specified, replace the VTV.
12. Reinstall the VTV with the brown side toward the TP.
13. Using a handheld vacuum pump, check the TP vacuum diaphragm.
14. If a vacuum leak is found, replace the TP.