Howdy.

Just had a new A/C compressor & clutch, belt, and drier/accumulator/what have you put in my car this very morning and was thrilled with the results. For 10 minutes.

NOW... the car is erratically doing the following:

1. With the A/C turned on and upon acceleration, I get a lurchy kind of slowness (more than I'd expect) and erratic acceleration throughout the RPM range and throughout all gears. It is particularly noticeable in 1st and 2nd, when accelerating from a stop where I climb spiritedly up the RPM range and then suddenly it feels as though the engine is towing 5,000lbs, then without warning, the car vrooms forward as if nothing was wrong... only to return to the slow lurchy thing a second later.

2. Again, erratically (maybe happened two or three times in an hour's operation), the A/C compressor sounds and feels as though it is locked in a cycle on/cycle off loop and it just keeps going until I turn off the A/C. During this, the idle is really bad, up down up down, shaking, almost to the point of dying.

Otherwise, A/C is nice, cold, and refreshing. But driving with the A/C ON is very unpredictable, jumpy, and powerless. Once I've had enough and the A/C is off, the car is completely normal.

Help?

 

Does the condenser fan work? It should be on whenever the compressor is on. If the fan does not run, excessive pressure will build up, putting a strain on the engine and causing the compressor to drop out and restart.

 

The compressor fan seems to work fine. It turns on right when the A/C button is pressed and turns off when the system is off. I observed it for about 5 minutes and it ran constantly while the A/C was on (this time working flawlessly... ugh). I hate things like this!

While sitting in the parking lot observing this, the air was cold, A/C cycled on/off at regular intervals, and idle seemed excellent. This time anyway.

 

So, revised symptom:

The A/C seems to run fine at higher, constant RPMs (i.e., freeway speeds), but when sudden drops in RPM occur, say, when I put the clutch in and freewheel, the tach will almost bottom out to the very bottom line and the A/C cycles off immediately, only to reengage as soon as the needle bounces back up to normal idle. Sometimes when this happens I will get the continuous cycle on/cycle off loop until things "stabilize". This "tach bottoming out" thing doesn't happen with the A/C switched off.

 

Try cleaning your IACV. The valve lets air into the intake to keep the engine idling at the proper speed. The extra load of the A/C requires more air than idling without A/C on. If the idle speed drops out of range, the ECU will cut out the A/C compressor to avoid stalling. Then the idle increases, and it cuts back on, resulting in cycling on and off.

This is all assuming the condenser fan works and the A/C cools OK once off of idle speed.

 

Thanks for the good info. I will try that tomorrow and report back. On a related note, I heard yet another thing yesterday that may help with troubleshooting. When the A/C turns on, I get a hissing "psssffffffttt" noise from behind the glove compartment area. Once it cycles off, the noise disappears. Any idea if this is normal?

 

That noise is normal, it's just the refrigerant flowing. Luxury cars make an effort to muffle it, Civics not so much.

 

Still working on getting this done

 

Still haven't done this and I wanna put in one more detail before I go ahead and try this cleaning (nervous). Today, I tried a little experiment by turning on the A/C while having the engine revved to 3,000 RPM while parked. As soon as the compressor kicked on, I lost like 1,000 RPMs and felt a tremendous drag on the engine even though my foot did not move off the accelerator at all. Dunno if this brings up any new flags to you...