Contents: Checking for functionality ⇊ Regulation ⇊
When the air conditioning clutch is engaged, a solenoid valve is activated, which supplies exhaust manifold vacuum to the idle speed increase control. This device opens the throttle valve just enough to maintain the set idle speed, but no more. The width of the valve opening is adjusted by a screw on top of the device.
Checking for functionality
1. Make sure that the engine, warmed up to operating temperature, gives, with all accessories disconnected, 800 rpm for models with a manual transmission and 750 rpm with an automatic. If the speed does not match the specified one, do not rush to adjust it.
2. Remove the vacuum hose from the top of the idle speed increase control valve and attach a vacuum gauge. There should be no vacuum. Turn on the air conditioner - a vacuum should appear. When you reconnect the hose to the control valve, the idle speed should return to the set idle speed.
3. If there is a vacuum in the boost regulator when the air conditioner is off, then disconnect the connector of the electromagnetic valve (supplying vacuum to the regulator), located on the heat-insulating partition. If there is a vacuum in this case, then the electromagnetic valve is faulty.
4. If there is no vacuum when the air conditioner is on, then you should check the voltage on the electromagnetic valve. It should be 12 volts. If the voltage is normal, then the electromagnetic valve is faulty. If there is no voltage (on the red conductor), then you need to check the voltage (12 volts) on contact A8 of the ECU device when the air conditioner is on. If there is voltage there, then the wiring is faulty. If there is no voltage, and the air conditioner is working properly, then the ECU device is faulty.
Regulation
1. If the idle speed increase control valve is working properly, run the engine at idle speed and disconnect the vacuum hose from the solenoid valve. Attach a hand pump to the control valve.
2. Pump out the air. The idle speed should increase to 1200 rpm. Remove the cover from the adjusting screw located on top of the regulator and, by turning it, set the desired idle speed.