System Testing

Fig. 39 Throttle position adjustment specifications:

3A-C & 4A-C ENGINES EXC. COROLLA FRONT WHEEL DRIVE

1. Run engine until it reaches operating temperature.
2. Check idle speed and adjust as necessary.
3. Ensure throttle positioner is released at idle.
4. On 3A-C and 4A-C engines, disconnect hose from second port from top of TVSV and plug the open port.
5. On all models, disconnect vacuum hose from throttle position diaphragm.
6. Ensure throttle positioner is set.
7. Ensure engine speed is within specifications, Fig. 39, with throttle positioner set.
8. Adjust speed as necessary by turning throttle positioner adjusting screw.
9. Connect vacuum hoses.
10. Ensure engine returns to idle speed within 2---6 seconds on 4A-C engines, or 3---10 seconds on the other engines after connecting hose.
11. If test results are unsatisfactory, test individual components.