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Hello,
First of all I'd like to start off by saying thank you for any help. I have an 02' EX with 185k and manual transmission.

When I turn my a/c on the clutch starts engaging and disengaging very rapidly making the car run really rough (making everything shake/vibrate). It cycles like 15 times within the 5 seconds. It makes for a very unpleasant idle, almost feels like it is going to stall. While driving, the a/c on every time the compressor kicks on the car develops a noticeable hesitation.

Please advise and thank you again.

 
Rep Power: 518

Hola.

Has someone recharged the AC prior to this complaint happening?

How long will the AC compressor clutch stay engaged before it begins kicking on and off?


When you turn the AC on, do both of the radiator fans turn on?

What is the idle speed of the engine? (AC not running)

Check engine light? Codes?


Do you have an AC pressure gauge set?

 
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Ezone:
a/c full charged recently (within 4 days).
I would say between 5-15 seconds.
Yes, both fans are turning on.
650-700 RPM
No quick engine light, throwing no codes. It hasn't stalled because of this issue, just pretty close.

No manifold/ gauge.

 
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I suppose the problem began immediately following the charge?

I would venture to guess the AC system was severely overcharged.

 
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It has not changed with the recharge this problem existed prior to charge. I took a video of the engine with ac on I can send. Would a severe overcharge cause that much vibration and almost stalling the engine?

 
Rep Power: 518

Does the AC cool normally if you are driving, or does it still kick on and off rapidly while driving?

 
Rep Power: 518

Gotta figure out which safety mechanism is causing it to cut out.

Low idle RPM would only affect at idle because the PCM can shut off the compressor when the idle speed drops below about 600 so the engine doesn't stall. It will kick back on as the RPM comes back up over 600 or so.
It would still be a working and cooling AC system above that engine idle speed.

If it was in my shop, I could connect my scanner and see the AC request and AC clutch on/off data, but IDK if that would gain me any good answers right now.

I could measure voltage changes at the system pressure switch to tell if that is what is causing it to kick in and out, but that's only part of the story.

Next step for me would probably be to connect a pressure gauge set and see what the high side pressure is when it cuts out. If it's hitting well over 400 PSI, that's a problem that needs figured out. Overcharged, blocked condenser, fans inop, internal blockage, are all possible.


Yes. Trying to turn the compressor on while there is already 400+ PSI on the high side puts one hell of a strain on the engine.

If the idle speed is simply too low, the added load of the compressor can make it unstable.

 
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ezone: It blows cold, but while driving it hesitates and rpms drop almost two-three hundred.

 
Rep Power: 518

So this rapidly kicking on and off only happens at idle?



The compressor does put a load on the engine whenever it kicks on. It takes something like 5 horsepower to run the compressor and you can really feel it when you have a smaller engine.

 
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Ok, I think it's definitely time to have a set of gauges hooked up it.

 
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I have owned the car for about a year now, this hesitation isn't the normal tiny engine load. When driving, it actually feels like it's jumping.

I was looking around for a short, a melted wire, and nothing...

 
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Update: I took the car for a two hour drive( hour up, ten minutes I between with it off, then hour back) the problem continues, yet it's no longer blowing cold air..on the return trip, the air started to get a bit colder, but so did the ambient temp.