SHO93OFF
New Member
I noticed that when the a/c is on and the car is in park, the idle will drop around every 20 seconds and then go back to normal, is this normal ?
Idle with a/c on
- Thread starter SHO93OFF
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Ishodu
SHO Member
Just the compressor cycling, Its normal.
SHO93OFF
New Member
That kinda sucks, its a little annoying, does it go away after a while ?
sdpatt
Sr. SHO Engr.
The EEC is programmed to raise the idle speed when the A/C compressor engages bu opening the idle air control (IAC) or idle air bypass (IAB) valve. Check the engine by observation to determine if the idle speed is dropping when the compressor engages or disengages. If it drops on engagement, you may try resetting the idle speed. If it drops on disengagement, it may be that the EEC is just raising the idle speed a bit too much when the compressor is turning. Try the idle speed reset for that one too.
A little background is that the compressor is a load on the engine and will require a greater IAB/IAC valve opening to maintain the programmed idle speed. The EEC should take care of it, but when the compressor clutch engages or disengages, there will be a momentary load change on the engine and the will be some speed change.
Lastly, and most importatnly, the 20 second cycle time is too short and indicates that you system is low on refrigerant. Get the system charged properly and the cycle times and A/C compressor engagements will come at less frequent intervals.
A little background is that the compressor is a load on the engine and will require a greater IAB/IAC valve opening to maintain the programmed idle speed. The EEC should take care of it, but when the compressor clutch engages or disengages, there will be a momentary load change on the engine and the will be some speed change.
Lastly, and most importatnly, the 20 second cycle time is too short and indicates that you system is low on refrigerant. Get the system charged properly and the cycle times and A/C compressor engagements will come at less frequent intervals.
projectSHO89
SHOless In St L
Well, a 20 second cycle time may be completely appropriate depending on the the ambient temperature, humidity, and the internal head load of the vehicle. Without knowing what the actual test conditions were, it's tough to draw a definite conclusion.
If Scott's recommendations regarding setting the idle speed don't resolve the problem, the IAC may be sticking and causing sluggish response. Cleaning sometimes helps. Reset idle speed after any IAC service.
Steve
If Scott's recommendations regarding setting the idle speed don't resolve the problem, the IAC may be sticking and causing sluggish response. Cleaning sometimes helps. Reset idle speed after any IAC service.
Steve
whiteknight
New Member
has anyone had this happen with the fan on, but not with it set to A/C?
(Dare I ask
)With the EATC, is there a specific setting for A/C, or does it come on simply by setting the temp to the colder settiing?
(Dare I ask
)With the EATC, is there a specific setting for A/C, or does it come on simply by setting the temp to the colder settiing?
