Hi guys, This is my first time in this forum :). Anyway i own a 1994 3VZ-FE Camry, just want to know is there a A/C idle control adjustment on my car? The reason i ask is that everytime when i try turn on the A/C, the idle speed will go up and down every 15 secs interval, i sat on my friend Camry few days ago (he own a 4 Cylinder Camry) when he turn on the A/C i didn't see his idle speed or up and down like my one....where as my one sometime it shack the whole car. Hope to here from u guys soon
Once you understand WHY the A/C is cycled On/Off/On ... AND understand the inherent response time lag in adjusting idle speed as load is applied/remove in a cyclical manner, you will find some other area of your life to obsess about. Really! :-)
This behaviour is indeed very irritating. I had a Tarago which did this, and it was caused by failure of the A/C idle-up vacuum switching valve (VSV). This is a 12V solenoid operated valve which bleeds air in the intake manifold to compensate idle speed for the load induced by A/C. The infuriating thing would only fail when hot, so whenever I looked for the fault on a cool engine I found nothing. I finally put it in the oven.
Then on the A/C electronic control unit (which was in the dash behind the glovebox) there was an adjusting screw which set the idle speed at which the A/C would cut in. This is normally set at a high idle speed, about 800 rpm, so when the VSV failed, and A/C was turned on, the idle speed would drop under the load, and then A/C would turn off at the ECU (not on the dash switch) and so idle would rise again, and then....
As a temporary measure I adjusted the speed at which A/C came on at the ECU to about 1200 RPM so it did not come on until I drove away, but that was still irritating as the car would sometimes stall.
These VSVs are not repairable, and unfortunately I don't know where the thing is located in a Camry, so perhaps someone here can supply that wisdom.
Geoff
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