greg1990964

Hey all. My A/c is cycling on and off on my 90 c2 cab. I am sure it is full of r12, used gauges. My condensor fan is working, I cleaned condensor with compressed air and water. My drain is dripping water as it should. I am toatally stumped. I am getting a temp at the vent of only around 54f early after starting car, and after driving around it creeps up to 72. same thing each time it cools and I head back out. Am I missing something? Could a fresh air servo be helping to cause this? I do see that I am not getting air on passenger vent, but would that have anything to do with a/c cycling on for 12 seconds, then off for 8 sec? Please help! it is 90 plus here now. I am going to pick up my 2 year old kid and her mother gonna give me the riot act about my a/c..
Thanks

jinos

You need to check the pressure on the low and high side. Could be under or overcharged. That's the first thing you need to do.

Makmov

What part of the ac is cycling, blower, compressor.

Yeah, I would say you have at least one servo out.

You should hear the fresh air servo if it's working when you hit the recirc but or if it's on fresh it should close when you turn the car off.

What are the pressures?

Could be a combo of things, and it's not the condensor that fills up with crud as much it's the evap, which can cause the system to be inefficiant.

greg1990964

I used my friends gauges, and I can't remember what it said, it think it was 220 high side and 130 low side? something like that. yeah, I hear and feel no difference when I hit the recirc button. never thought of the evaporator having crud on it. How do you clean that? I guess I need to play with the servos, but would that effect the cycling compressor?

Makmov

130 is high for the low and it should cycle with the AC e.g. 30-50 then 50-80 or so as the compessor cycles,

Probably need to put the guages back on and do a static read, and then a read with it running.

So there is a issue with compressor, perhaps leak, or expansion valve if those numbers are indeed correct.

Generally, you just replace the evap, you have to take the airbox out, which means the fuel tank, fire wall, and split the case. Yes very time consuming and involved, but nothing terribly difficult.

A good time to do the servos too, which is sounds like at least 2 of the 4 are inop: the footwell flap and fresh air flap.

greg1990964

I will go put it on the gauges again. Do you know the correct high and low side numbers for r12? That is where I should be starting from. No leaks in system as it had pressure after sitting long time. Getting no air from oassenger side vent and only have def vent def means the fan is not working on passenger side and prob have fresh air servo issues. My condenser fan runs, seems to be on hi. Is the low speed really low. Like less than a hair dryer? It seems to really be blowing pretty good. Thanks