Erratic idle w/ A/C? - Focaljet

**lm1d** · 03-04-2007, 04:52 PM

My daughter has a 2.0 duratec, 2000 ZX3. The car idles erratically when the A/C compressor runs, it idles fine when it is off. The idle moves to 2000-2500 and back when the a/c switch is on, it seems to not matter whether or not the compressor is running.

When the a/c is switched off, everything is fine.

Any thoughts? Can't seem to find much by doing a search.
Thanks!

**MadDawg-Zx3** · 03-05-2007, 01:03 AM

hmmmm I was thinking maybe an IAC concern but it only happens when the A/C cycles. That stumps me.

maddawg

**MEJ684** · 03-05-2007, 12:58 PM

Isnt the a/c system controlled by vacuum? Im thinking a vacuum line is off causing the crazy idle spike.
What is the idle like with the a/c off? Normal it should be around 750 rpm.

-Mike

**lm1d** · 03-06-2007, 01:26 PM

I can unplug the pressure switch under the right front fender, the compressor quits cycling and the idleing stops. Does anyone have a troubleshooting chart for that pressure switch? I think it's a high/low switch because it have 4 wires in it.

**MadDawg-Zx3** · 03-07-2007, 02:04 AM

is the A/C cycling on and off every few seconds? If it is and the Fans are staying on you need to replace the Switch

maddawg

**lm1d** · 03-08-2007, 11:50 AM

Yes, a/c is cycling every few seconds @ idle. I can't seem to find one with 4 wires, only 2. Guess I'll have to go to the dealer.

03-04-2007, 04:52 PM	#1
lm1d TEAM Member Join Date: Aug 2000 Location: Cedar Hill, TX, USA Posts: 139	Erratic idle w/ A/C? My daughter has a 2.0 duratec, 2000 ZX3. The car idles erratically when the A/C compressor runs, it idles fine when it is off. The idle moves to 2000-2500 and back when the a/c switch is on, it seems to not matter whether or not the compressor is running. When the a/c is switched off, everything is fine. Any thoughts? Can't seem to find much by doing a search. Thanks!

03-05-2007, 01:03 AM	#2
MadDawg-Zx3 Senior TEAM Member Join Date: Apr 2001 Location: Los Banos CA Posts: 1,399	Re: Erratic idle w/ A/C? hmmmm I was thinking maybe an IAC concern but it only happens when the A/C cycles. That stumps me. maddawg

03-05-2007, 12:58 PM	#3
MEJ684 TEAM Member Join Date: Nov 2006 Location: Erie, PA Posts: 945	Re: Erratic idle w/ A/C? Isnt the a/c system controlled by vacuum? Im thinking a vacuum line is off causing the crazy idle spike. What is the idle like with the a/c off? Normal it should be around 750 rpm. -Mike

03-06-2007, 01:26 PM	#4
lm1d TEAM Member Join Date: Aug 2000 Location: Cedar Hill, TX, USA Posts: 139	Re: Erratic idle w/ A/C? I can unplug the pressure switch under the right front fender, the compressor quits cycling and the idleing stops. Does anyone have a troubleshooting chart for that pressure switch? I think it's a high/low switch because it have 4 wires in it.

03-07-2007, 02:04 AM	#5
MadDawg-Zx3 Senior TEAM Member Join Date: Apr 2001 Location: Los Banos CA Posts: 1,399	Re: Erratic idle w/ A/C? is the A/C cycling on and off every few seconds? If it is and the Fans are staying on you need to replace the Switch maddawg

03-08-2007, 11:50 AM	#6
lm1d TEAM Member Join Date: Aug 2000 Location: Cedar Hill, TX, USA Posts: 139	Re: Erratic idle w/ A/C? Yes, a/c is cycling every few seconds @ idle. I can't seem to find one with 4 wires, only 2. Guess I'll have to go to the dealer.

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