A/C Update**

[Bigmacneb1]

Noobie. I tried searching but can't look up the word ac or variations. Thank you in advance for any advice. 1991 318is, the air blows cold, however there is a clicking, like something turning on, for maybe 10 seconds and then turning off. It then does this every 45-60 seconds or so. Each time it comes on I get a dip in RPM and a loss of power if I am under throttle. When coming to a stop I get the fluctuating idle, in one case when I depressed the clutch when coming to a red light the idle came down to 500 and then stalled.

It only does this with the A/C on.

I just purchased this car... Didn't do it on the test drive, which i conducted all day!

UPDATE** Got the car back from the shop this morning. it had previously been converted to 134. They put in just over a pound, no leaks. Problem is the A/C compressor continues to cycle on the highway. So I drove it straight back to the mechanic and it doesn't cycle at idle, or while resting any more. Thoughts somebody. It's really annoying driving down the highway for the compressor to cycle on and off every 10 seconds. The loss of power jerks the car when it comes on, then speeds up when it turns off. Thoughts anyone???

[lcgtrplr]

Your AC compressor is a little low on freon and it is cycling on and off because of that. The cycling shows up more on a 4 cyl motor thus the change in rpm/power.

[Bigmacneb1]

thanks. Is there a way to tell if the AC system has been changed out so I can know if I can refill or if it needs all new AC?

[shutter]

Another thing to check is the low/high speed thermal switches for the aux fan.  Look through the grill and the aux fan should turn on when the AC is on.  It's prob working if it blows cold, but maybe it's intermittent?  My low speed wasn't turning on at all, but it was trying to and definitely making a ticking sound.  It actually made me nervous when it first went, nobody likes to hear a tick

[lcgtrplr]

The fittings will have been changed to a larger size (i believe) and if it has been changed someone should have written it somewhere under the hood.

  If it has nor been changed the shop will pull your freon out and put it all back in and whatever needs to be added will be done at that time.

It looks like you are not very low so the cost shouldnt be outrageous versus having it all switched over to 134.

[Bigmacneb1]

I've set up an appointment to take the car to the mechanic on Monday. Tonight I'll check the Aux fan and do a little more looking, but I'd like the mechanic to let me know any other issues. I'll keep you posted.
Thanks

[Bigmacneb1]

Slight update. Auxillary fan is on the entire time, seems to be working properly. The click on and off is the Compressor (as I watched it) It comes on for 7 seconds then off for 10-15.
Do you think that this is due to low refrigerant, or a bad compressor? Thanks guys.

[shutter]

Chk the wires too, could be a short.  I had one once right after the compressor harness, but that was a Chevy

[Bigmacneb1]

bump for update

[D. Clay]

The idle speed fluctuation is likely the idle control valve(ICV). It should open and let more air/fuel into the intake to increase idle speed when the A/C cycles. It's at the back of the motor by the valve cover/intake. Check the rubber line from the valve to the intake.  Is the check engine light on? The ICV itself may be bad.  The A/C cycling frequency is a separate issue.

[Bigmacneb1]

The ICV has been replaced a few months ago. I'll double check the connections to make sure nothing has been jarred lose.
The Check Engine light is not on.
Any ideas on the A/C cycling?