Idle Up Control Valve: Testing and Inspection

Fig. 62 Idle-up system.:

Fig. 46 Air bypass solenoid valve connector terminal identification.:

1. Warm engine to normal operating temperature and run at idle.
2. Turn off all accessories and connect tachometer to engine.
3. Disconnect electrical connector at air bypass solenoid valve.
4. Check idle speed and adjust as necessary.
5. Apply battery power to terminal A and ground terminal B, Fig. 46, and ensure engine speed is 1250-1350 RPM.
6. Apply battery power to terminal C and ground terminal D and note engine speed.
7. Apply battery power to terminal E and ground terminal F and note engine speed.
8. Ensure engine speed in steps 6 and 7 is 850-950 RPM on vehicles equipped with manual transaxle, or 1000-1100 RPM on vehicles equipped with automatic transaxle.
9. If engine speed is not within specifications, adjust by turning respective adjustment screw.
10. Reconnect electrical connector at air bypass solenoid valve.
11. Check idle speed and adjust as necessary.
12. Check resistance of valve as follows:
a. Disconnect electrical connector at valve.
b. Check resistance between terminals. Resistance should be 17---23 ohms between terminals A and B and 27-38 ohms between terminals C and D and between terminals E and F.
13. Check A/C idle-up signal as follows:
a. Warm engine to normal operating temperature and run at idle.
b. Attach voltmeter between A terminal and ground.
c. Turn A/C and blower motor switches on.
d. If meter does not show battery voltage, check A/C relay, A/C switch, blower motor switch, fuse and wiring harness.
14. Check power steering idle-up signal as follows:
a. Warm engine to normal operating temperature and run at idle.
b. Attach voltmeter between D terminal and ground on 1986 models, or between terminal F and ground on 1987 models.
c. Turn steering wheel fully right or left and ensure meter shows zero volts.
d. Release steering wheel and ensure meter shows battery voltage.
e. If voltage is not as described, check power steering switch and wiring harness.
15. Check high altitude compensation as follows:
a. Warm engine to normal operating temperature and run at idle.
b. Attach suitable vacuum pump to atmospheric pressure sensor.
c. Attach voltmeter between terminal D and ground, apply 6.10 inches on 1986 models, or 3.35 inches on 1987 models, Hg of vacuum to atmospheric pressure sensor and ensure voltmeter reads zero volts.
d. Release vacuum and ensure meter shows battery voltage.
e. Attach voltmeter between terminal F and ground, apply 3.35 inches on 1986 models, or 6.10 inches on 1987 models, Hg of vacuum to atmospheric pressure sensor and ensure voltmeter reads zero volts.
f. Release vacuum and ensure meter shows battery voltage.
g. If voltage readings are not as described, check atmospheric pressure sensor and wiring harness.
16. Check hot idle compensation as follows:
a. Warm engine to normal operating temperature and run at idle.
b. Attach voltmeter between terminal and ground.
c. Remove air cleaner upper case assembly.
d. Heat intake air temperature sensor to more than 131°F.
e. If voltmeter does not show zero volts, check intake air temperature sensor.