AC problem on 1991 Camry

[Gopal]

I am a bit confused. Is this about 7" box that sits just opposite to the steering wheel on the firewall?

Also, how do I adjust the idle rpm? I called my mechanic - he says it is computer controlled and cannot be adjusted.

Thanks!

[Doctor J]

The idle-up solenoid is a small cylindrical part that is bolted to the firewall on the passenger side. The idle speed is electronically controlled but the base idle rpm is adjusted by turning the screw covered by black round plug on the throttle body.The idle speed for A/C is increased by applying vacuum to the diaphragm that opens throttle plate bypass pipe.The solenoid opens the vacuum flow to the diaphragm. The Idle speed for A/C is adjusted by turning big hex plastic bolt near the diaphragm when A/C is on. For more info refer to Autoshop 101.com by K.Sullivan, Technical articles, EFI#2 Air induction system, page 11.

[Gopal]

Doc, That's a great piece of info. Thanks!

How sensitive is the screw? I mean if I am not careful can I completely screw (pun!) it up?
Is there a correct method of setting the ilde-speed? Any links towards that?

[Doctor J]

You need to attach tachometer to the engine,
let the motor to warm up,
turn all accesories off,
fans must be off .
One to two turns counterclockwise should be enough.

[Gopal]

I do not have a Tachometer and I'm not buying one for just this purpose.

Is there a tree-shade mechanic method for the same?
Can I ask my friend to keep looking at the Tachometer in the gauge cluster while I loosen the screw slowly?

[Doctor J]

It may give you about 100 rpm error.
Have you checked idle up solenoid resistance?

[Gopal]

Thanks!
I can live with +/- 100rpm. As mentioned in the other thread, I am changing the timing belt this weekend. I'll wait and see if this changes the rmp any. Will keep you all updated.

Oh! the solenoid. No not yet... I'll have to go home to do that.

[Kep]

You might check with some of your auto parts stores in the area. Many of them loan out (with a deposit) tools. Maybe a timing light. You may need some specialty tools to change out the timing belt too.

Kep