Another idling problem

[digital_racer]

My car just came from the shop a few days ago. I had the timing done and replaced the A/C compressor. The guy who did the A/C told me that the vacuum solenoid is not working properly. As a result, every time I turn on the A/C the rpms drop bet. 750 to 1000 rpms so he set the throttle at 2000 rpm when the A/C is off. The thing opposite the throttle is what the mechanic says is faulty.

[punter]

Yes thats you A/C ide up (puts the revs up when the A/C is switched on)

Whats your question?

[digital_racer]

Do I need to replace the solenoid that he said, Or can I just bypass it by plugging the vacuum lines?

[digital_racer]

Still need help. I took the car to the shop and all they did was adjust the idling from 1,500 rpm down to 500. But this time, i need to turn on the air conditioning to put the idle at 1,000 rpms otherwise I'd stall.

I want to post a picture but when I tried, it only puts in an html link.

[94_Rolla_Guy]

there are 2 methods of idle adjustment,

for the A/C there is a solinoid (A/C idle up VSV) on the fire wall just behind the throtle body and intake, if that is stuck closed then it will want to stall with the A/C on. If it is stuck open the engine will idle at 1200-1400 rpm. I have this problem i have about 4 of these valves off junkyard cars and they are all intermitend!!!

then there is the IAC (idle air controller) (white plastic thing with electrical plug on bottom of throttle body) if this jams closed the idle will be low, open high. There is a way to test this, turn all electrics off headlights, heater motor, defroster,wipers everything, car should idle at 700rpm +/-50rpm then turn on your headlights, it should now idle at 800 rpm +/-50rpm (for save measure i would give the throtle body a real good cleaning, (take it off and apart) to avoid any problems here)

from what ive read the idle speed is supposedly set at the factory and isn't suppose to be adjusted....???

If they have played with the set screw it may need to be recalibrated meaning A/C off every electrical gizmo off and set the screw to 700-750rpm don't go lower than 700 as it will start to run rough.. (this proceedure would be my best guess as the factory service manual doesn't have a proceedure for this)

[digital_racer]

I took it back to the shop again. The mechanic says that the solenoid for the A/C can be adjusted and he did. Now the idling is at 1,000 rpm rising to 1,100 rpm when the A/C is on which is just the way it worked when brand new 10 years ago.