Curb Idle Speed Adjustment

Fig. 5 Adjusting RPM. 4-156 engines:

Fig. 6 Idle-up adjustment. 4-156 engines:

4-156 ENGINES
1. Set parking brake and place transaxle in Neutral position.
2. Turn off all lights and accessories, then disconnect radiator fan electrical connector.
3. Connect tachometer, then start engine and allow to reach normal operating temperature.
4. On models equipped with A/C, disconnect cooling fan electrical connector.
5. On all models, allow engine to run at 2500 RPM for 10 seconds, then return to idle.
6. Wait two minutes, then note engine RPM. If the idle speed is not as specified on the Vehicle Emission Control Information. (VECI) label, turn adjusting screw to obtain correct idle speed, Fig. 5.
7. On models equipped with A/C, set temperature control lever to coldest position and turn on A/C.
8. Set engine speed to 900 RPM by turning idle-up screw, Fig. 6. Ensure A/C compressor is operating during idle speed adjustment.
9. Connect cooling fan and radiator fan electrical connectors, then remove tachometer.