Every time I turn on my ac, and I come to a stop sign or red light, the compressor starts clicking like crazy and the rpm's in my car go up and down. It almost seems like the car is going to shut off on me. However, when I accelerate or turn off the ac, the clicking stops and the car runs normal. Any one out there with any advice? Or is it even safe to keep on driving the car with the ac on? The ac was just recently charged to its adequate range as I filled it using the gauges making sure I wouldn't overfill or go under.

 

If you got two electric fans make sure they both run when you turn your A/C on; other wise you will over pressure the system. If you have high press. switch it will cycled the Compressor off and of course affect idle. This will come into play when air flow through the Condenser is low but not affect you while you are moving down the road.

 

Ill check to see if both fans are running. In the case where there both not running, any easy way to get this fixed, or something that needs to go to a shop? Also is it safe to keep on driving the car like this in the meantime with the ac on?

 

Do not use the A/C untill problem fixed.

As mentioned it may be a high head pressure problem from either low air flow, [fans not working] or an overcharge.

Using a gauge to charge an A/C system is not accuret, too many other factors to take into account.

The only accuret way is to recover what is in the system and then recharge with the proper amount, [23oz (94-02), 30oz (93), 32oz (90-92)].

As mentioned, make sure both rad fan and condensor fans are running when A/C is on. 94

 

If this quick cycling continues while you're at speed, you're more than likely grossly overcharged. The air flow thru the radiator / condensor would be sufficient at speed.

One other thought; you may have contaminants in the a/c system.
Has the system suffered any failures in the past?
Grenaded Compressor?
Hose broke / burst?
If a blockage were to happen at the expansion valve, the high pressure side would be effected.

P

 

the system has never had any prior problems. Other than the leak ive had (since I always need to recharge it every summer) the ac has always worked and blown cold air. As far as starting from scratch again and see if that works Ill make sure not to trust the gauges as theyve proven not to be too accurate. Hopefully thats the problem im having or I guess ill have to bring it into the shop for further diagnostics.

 

As a matter of good mechanical practice I've always used a charging station when servicing a/c systems. That way I can not only recover (and not vent) refrigerant but also pull a vacuum (and confirm/deny a leak) and recharge (and add refrigerant oil and a florescent dye) a system.

Pulling a vacuum can be very important in that it will boil off and evacuate any moisture that may have gotten in.
The gauges are an important tool and you are correct in using them. They can be most useful in diagnosis but are all but useless when it comes to recharging. Todays cars now specify a volume of refrigerant, thus the use of charging stations.

I think you will save a whole bunch 'o money (and aggravation) by having 'the shop' take a look

P

 

thanks for the advice. Do you also reccomend not driving with the ac on, as the the other member posted or will it not hurt the engine(even though the rpms go up and down when stopped).

 

The only things the engine is seeing is additional wear to the a/c drive belt, accelerated wear to the compressor clutch and an over active Idle Air Control valve (IACV).
If you can avoid using the A/C, I would suggest so.
It's not that I want to condemn you to driving in 90degree heat w/o A/C but the quicker you get it looked at, the better.

P

 

You've been a great help. Looking to see if i can get it into the shop early next week. Hopefully they tell me it was just overcharged. im going to try and see if by cleaning the throttle body with throttle body spray helps as well. But like you said the earlier I get it looked at, the better. Cant stand driving in this heat without the ac, but id rather not use it in order to not wear out the other parts. Ill keep posted what they find out.

 

Let me know how it turns out.

P

 

So i cleaned the throttle body late last night and went out to go try out the car..the problem is no longer there. This morning on my way to work, no more clicking from the compressor or rpms going up and down when I come to a stop. Im also thinking the cold air intake I have, might have not been put all the way into the throttle body since it had been removed recently to change the starter. Maybe that was causing the engine to have a rough idle and therefore engaging the compressor clutch to engage all the time?? Hopefully the problem is gone for good and not a temporary fix.

 

Just finished another thread on this exact same topic. Cleaning the TB/IACV cleared up my problem as well.

 

Actually, this doesn't make a lot of sense but hey; stranger things have happened.
I can understand the idle hunt from the dirty TB, but it shouldn't have effected the A/C. Perhaps an interaction with the load compensator......

I'd say rejoice in your good fortune and just keep a wary eye. I suspect the condition may rear it's ugly head again.

P

 

Im praying it stays like that..I also would try to move the steering wheel while in park (as that would also engage the compressor to click and the rpms to go crazy) and not a sign of the problem. Also checked if both fans are running and they are. Very strange indeed...