When the car is idling and the A/C is turned the engine will shutter hard and/or turn off. I've already replaced the IAC valve; it was working for a little, but now it's back to shutting off.

The only other things I can think of is the electronics controlling the IAC. Any ideas?

2004 dodge neon r/t SOHC

  • Does the ECU raise the idle when you turn on the A/C? – Timo Geusch Aug 30 '11 at 14:36
  • stays around 900 rpm – DustinDavis Aug 30 '11 at 16:13
  • I'd research if it's supposed to raise the idle - most cars I'm aware of do as the a/c compressor can add a lot of drag on the engine. – Timo Geusch Aug 30 '11 at 18:42
  • when the a/c turns on the IAC will open to keep the car at 900rpm. If the IAC didn't open the car would drop to 500rpm and die. – DustinDavis Aug 30 '11 at 19:02

I would check belt tension and rotation of the pulley on the compressor.

The compressor may be exerting more drag then it is supposed to causing a further drop in RPMS then the IAC is compensating for and so causing it to stall.

It may be the pulley itself seizing which you may be able to recover with some corrosion cleaner, lubricant etc. Otherwise it may be internal of the compressor.

Also, there is supposed to be a certain amount of oil in the refrigerant to lubricate the system, perhaps you have a leak that has caused loss of this lubricant and again the compressor is taking more effort to rotate.

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  • all good posibilities. I'll check them out. – DustinDavis Sep 1 '11 at 3:08
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    Ended up just buying an SRT-4. No more shuttering :) – DustinDavis Sep 20 '11 at 3:37
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    Heh, expensive repair, enjoy the new ride. – ManiacZX Sep 20 '11 at 18:02

Overcharged system, my gf had the same problem on her 02 celica gts, I was troubleshooting and hooked up the gauge to check the refrigerant and it showed over 100 psi so I purged the line down to around 40 and engine shudder solved.

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