Intermittent A/C Problem - cold at idle, warm during driving

thisxstyle

New Member
Jun 15, 2021
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San Antonio
I'm hoping to get someone that has some feedback about my recently purchased 02'.

I bought this car as a project car, and went to repair the A/C. The car had a small hole in the discharge line, so I ordered one, replaced the line, the o-rings, drier, orifice tube, then had the system vacuumed, I checked for leaks and refilled with 34oz of refrigerant. For the first day, the a/c worked perfect, however now I have a super annoying problem where the a/c only works at idle, and doesn't want to work when I'm driving. It continuously cycles warm, then cold. I've noticed that under any acceleration (pedal at 20% or 50%) will cause this warming to occur where the air blows at around 70 degrees. When I let off of the pedal, or slow to a stop the a/c returns to the correct temp of around 40ish degrees.

I have checked the clutch gap, and it is around .020, I've replaced the high and low side pressure switches, verified that the air inlet and mix door isn't blocked in any way and functioning properly. I cannot seem to get the problem to replicate at idle so I haven't been able to use my a/c gauges to see if anything is irregular. I read suggestions of pulling over as soon as the car starts blowing warm to look at the a/c compressor clutch, however, as soon as slow down to pull off the system functionality returns to normal. Upon pulling off I did notice that the line containing the orifice tube was warm, so I re-evacuated the system and installed a new one to eliminate that as a problem.

Does anyone have any suggestions as to how to go about troubleshooting this? Thanks
 
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TIGGER

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Mar 6, 2000
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Interesting problem you have. Sounds like something is happening with the compressor above idle. That is the only thing that makes sense to me. If the compressor is not turning you are not going to have Cold air in my opinion. I would hook up your gauges and run the car at idle. If and once the ac is working properly I would wedge something in the throttle body and bring the rpm up and monitor things and see if you can pinpoint what is happening.

The AC pump went out on my wife’s ragtop shortly after we got it. The AC pump would seize randomly. Air would stop being cold. Car would overheat or get much warmer than normal. And then you would smell something burning(belt). I figured out what was happening by doing the same thing I mentioned above.

Hope this helps some.
 

7991LXnSHO

wanna catch the space herp
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Sep 1, 2010
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Just a different idea in addition to compressor issues. The earlier AC systems have an acceleration cut out switch. I have no idea if it is computer controlled or how it’s handled on an 02, but the compressor disengaging under full throttle is what you describe under any acceleration.
 

KRUISR

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Apr 16, 2015
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I would go with either not enough refrigerant or not enough air flow across the condenser.
 

manicmechanic007

Active Member
Sep 26, 2017
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The WOT relay may be cutting the compressor out. It's the sometimes elusive grey one. It is the wide open throttle cutoff relay. There are pressure charts and compressor on off time charts in the manual for those of you who do not have the cert or recyclers -ie evacuate and recharge capability. You can figure out the charge level yourself without gauges pretty close. I still use R12 in those old ones if they are worth it. It's R1234yf I'm pissed at currently gonna cost me another 10K for a new machine and identifier