rough idle w/ AC

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10/21/2010, 10:01 AM
etlsport

rough idle w/ AC

this has been going on for some time now, didnt see anything about it posted..

when i have the AC on, the VX runs a little noiser and definitely rougher, the whole car has a rumble to it. if i turn the ac off it will continue until i drive maybe 1/4 mile then it idles smooth as silk..

anyone seen this or know what to do about it? i rarely use my AC anyway, but it is annoying.

ive cleaned the IAC a couple of times, my next step i think is the TPS and EGR (which ive cleaned a few times) since im over 100k anyway
10/21/2010, 10:25 AM
tom4bren

Does it do it with the defroster too?
10/21/2010, 10:29 AM
etlsport

anytime the AC compressor is on. with the fan blowing and no air conditioner its fine
10/21/2010, 10:47 AM
tom4bren

The part that's confusing me is that it continues for a while after you turn off the AC. Does the idle kick up when you turn the AC on? Is there any delay between when you turn the AC on & the rough idle starts?
10/21/2010, 12:21 PM
etlsport

Yes it is more or less instant when I switch it on except when the engine is cold. When I switch it off it gets better but doesn't go away until I've driven a block or two. No notable jump in rpm
10/21/2010, 12:54 PM
tom4bren

IIRC there's supposed to be a circuit to bump up your idle when the AC is on.

I'm clueless right now but I'll be thinking about it on my commute home tonight.
10/21/2010, 02:44 PM
etlsport

Quote:

Originally Posted by tom4bren

IIRC there's supposed to be a circuit to bump up your idle when the AC is on.

I'm clueless right now but I'll be thinking about it on my commute home tonight.

that was my thinking. if i hold the brake and give just a small amount of gas (bump from 800 to 900 rpms, it smooths out a lot. which is why TPS and IAC were my two thoughts
10/22/2010, 02:37 AM
WILLY

Sounds like what i just went through last week,my ac leaked its 5 ounces of oil out a few month ago and the bearing started rumbling so i just ran without ac on,then even without it turned on it started howling and i knew it was a matter of time b-4 it seized up and stranded me so i figured out the length of belt i would need to eliminate the compressor until spring and when i have extra cash/time.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Poly-Rib&174;-Belt-Dayco_19270624-P_1063_R|
10/22/2010, 07:34 AM
etlsport

the AC works perfectly. blows cold, the compressor and pulley dont make any noise at all. the idle goes rough when the compressor switches on
10/22/2010, 08:51 AM
Luna X

ya might have to try the 'ol baby powder trick to see if you can spot any vacumn or intake leaks... ;)