So i finally got my ac going but when i turn it on at times the idle drops really bad or even just makes the car turn off. When the ac is off it idles at 1500 or sometimes right at 1000. I was told i need to adjust my idle. But then why is it high when its off. I know Someone had messed with the little screw on the throttle body(air/fuel mixtuure) and i was told your not supposed to mess with it. Dont know how to set it back or adjust the idle properly. Any help would be appriciated, thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiTR &raquo;</TD></TR><TR><TD CLASS="quote">So i finally got my ac going but when i turn it on at times the idle drops really bad or even just makes the car turn off. When the ac is off it idles at 1500 or sometimes right at 1000. I was told i need to adjust my idle. But then why is it high when its off. I know Someone had messed with the little screw on the throttle body(air/fuel mixtuure) and i was told your not supposed to mess with it. Dont know how to set it back or adjust the idle properly. Any help would be appriciated, thanks.</TD></TR></TABLE>

Not true. That little screw is your idle adjuster. Even if your Idle is at 600, when you turn that A/C on there is no reason why your car should stall. You must have a short somewhere for it to do that.

 

Any ideas of where it might be that can be causing it to do so.....

 

If you suspect the idle needs to be reset, preform these steps in order:

Run the engine to fully warm (fans kicks on).

Disconnect the IACV plug. (back of the intake manifold near the throttle body.) If the engine stalls, check or replace the PCV valve. If it still stalls, turn the screw counter clockwise with the IACV plugged in to allow it to maintain idle. Once idle is maintained, disconnect the IACV again and let it idle.

Adjust the screw 1/4 to 1/2 turn every 5-6 seconds until 450RPM is reached and maintained. This is the engines base idle speed.

Plug in the IACV, engine RPM should jump to 700-750RPM within a few seconds.

The reason for this is to give the IACV its midpoint of adjustment, so it can add, or take away the most air possible when needed. If your idle is too low, the IACV will max out to keep the car running, when when another load comes in (power steering or A/C) the engine cannot add any more air without pressing the throttle, effectively stalling the engine.

 

Dam sounds kind of confusing but ill try it tomorrow, thanks. For now i have the vacume line behind the intake manifold unpluged and for some reason it works fine, just idles a bit higher when the ac is off at times. I was thinking maybe the iac valve was causing it cause it started acting up a while back, so i made a gasket for the throttle body to block it off. But ill try this out cause i really need to fix it properly.

 

After thinkning bout this i dont thinking testing it would work since i already have it blocked off with a home made gasket for my throttle body.

 

Well, there is your problem. PCM cannot compensate for the load the A/C places on the engine because the means to compensate has been blocked. Why you did that I don't know...

I suggest you "undo" that.

 

It was done by someone that had worked on the car when it had started idling funny long ago, i guess it was like a quick fix that ended up leading to more problems in the future. Well ill get that (iacv) replaced and get a normal gasket for my tb. Hope it fixes the problem. Thanks for the help.