turning EATC on causes rough idle

[Randall]

hey everyone,
I can't figure out why when I turn on the EATC to automatic, or even MAX ac, the car suddenly studders and loses 400 rpms at idle and nearly dies, only seconds later to begin flucuating between 500 rpms and 900. I was advised to do the idle reset procedure, and did, but it still does this. I didn't notice this problem before my battery was disconnected last week for a day. The problem goes away when I turn off the EATC. Thanks for any help!

 

[yamahaSHO]

Your AC may be dragging it down. When you turn on "MAX AC" or "Automatic" to a cooler position, your air conditioner kicks on. Do you have any funny noises coming from it? Do you get cool air from you vents? I would look into compressor being the culprit.

Does it do the same thing when you hit the defrost button?

 

[Randall]

Well, I definetly hear the AC coming on with a few clicks from the engine bay, and extremely cold air comes out of the vents, and when the fan is on high for defrost it does it too.

 

[greenbeanmtx]

If its not making any growling noises(the compressor) then id suggest you actually drive it like that for a day or so. Even if i do the idle reset trick none of my shos will actually return to acting 100% until i drive it a couple days. They would act similar to what your saying and occasionally comming up to a stop they would actually stall on me. My 93 did this for a couple days where as my 89 went away about 3 or 4 hours after i did it. Drive while the air is on and see if that changes anything.

Did you disconnect your battery lately? If not then disregard what i just said. Theres no need to reset idle if the battery hasnt been disconnected. If thats the case then i agree, your compressor might be the culprit and the bearing could be going bad. Good luck with it, hopefully its not major

 

[SHOZ123]

Could be a vacuum leak behind the dash.

 

[Randall]

I was wondering if it was a vacuum leak behind the dash, but where do I look? I did have to replace the EATC unit a few weeks back, but this problem is only a few days new. Thanks for any help!

 

[sdpatt]

If it didn't do this before you disconnected the battery, the problem is stil llikely that the idle needs to be properly reset. This time, let the engine idle for at least 30 seconds before adding the A/C, alternator and power steering loads.

 

[Randall]

I just wanted to say thanks sdPatt, the last time I did the idle reset procedure, I turned on the A/C right away, but this time, I did it the way you suggested, and so far the problem is gone! Thanks again!