Really? A/C Compressor Stumble Is Normal?

[Scarlet2003]

I am curious as to what this means: "can feel a/c clutch engage and disengage due to lack of air flow." Due to lack of air flow? Is this why it bucks and surges only at idle? I also get no AC at idle when it does this. Sounds like a bad fan, surging aside. I cold put up w/ the surging if I had AC when it is 98 degrees outside and a 72 degree dew point.

This car is a PITA.

[cherrypopper20]

Hey guys this thread is kind of dead, but my gfs pt is having the same problem... its a 2001 pt non turbo...
so out of this thread was the aswer
-oil in plugs due to vavle gasket
-raditor fans
-map senson/cam sensor/upstream and down stream oxi. sensors?
...
stumbling when gas is applyed, sputters way worse when ac is on, loss of power through out power band... NO CHECK ENGINE LIGHTS.
Please help me.

[Hooligan]

How many miles? Has plugs and wires been changed? Do you have any maintenance records? Answers to these questions will help us to help you.

Welcome to the Forum!!!

[cherrypopper20]

It has 110k miles, plugs and wires have been change, its has had a rebuilt motor and new fuel pump...
its a bad sputter when ac is on like car basicly shakes, when ac is off it sputters when gas is on most noticable from 1k-2k but does it at all rmps, big loss of power through the whole power band...
it is not a trans issue due to it sputters when in neutral. its a 2001 pt non turbo.
Has no check engine light on.
Anyone that has had this problem which looks to be alot, please let me know what fixed it for you...

[Scarlet2003]

Hey New PT - you described my situation perfectly. I was told I need $1300 in new compressor work and promptly left (on a 95 desgree Southern day) and as long as it was moving I had cold air. This the wife's car and it turning into a real PITA and I am beginning to think it is a POS.

[fljohnboy]

Where is this AC idle valve and what does it look like?

[quicksilverdon]

Originally Posted by fljohnboy

Where is this AC idle valve and what does it look like?

It's idle air controller.
This thread has a pic:
PT Cruiser stalling...

[fljohnboy]

so is the idle air control (iac) the same as an air conditioner valve just termed different?

[quicksilverdon]

Here's what I know:
When A/C is turned on, the IAC is supposed to increase the idle speed.
The A/C has 2 shut-off that will open the clutch (shut off A/C) :
1) Low pressure switch
2) high pressure switch

If the freon pressure is too high or low, A/C will shut off to prevent compressor from burning up.

[CREWZIN]

Found this in a search:

Idle Air Control Valve

The idle air control (IAC) valve assembly controls engine idle speed and provides a dashpot function. The IAC valve assembly meters intake air around the throttle plate through a bypass within the IAC valve assembly and throttle body. The PCM determines the desired idle speed or bypass air and signals the IAC valve assembly through a specified duty cycle. The IAC valve responds by positioning the IAC valve to control the amount of bypassed air. The PCM monitors engine rpm and increases or decreases the IAC duty cycle in order to achieve the desired rpm. The IAC valve [is also] part of the throttle body assembly...

The PCM uses the IAC valve assembly to control:

- No touch start

- Cold engine fast idle for rapid warm-up

- Idle (corrects for engine load ex: when A/C is ON)

- Stumble or stalling on deceleration (provides a dashpot function)

- Over-temperature idle boost.