A/C problem.

[mechtech]

If it gets too hot, the high pressure switch will cut off the compressor clutch power [same for the low pressure switch].
The idle is raised with the extra load of the AC, and your idle air control valve may be gummy - sticking. When the AC cycles [normal], it therefore won't come back down correctly.

 

[mcrn]

Hi and thanks in advance. I have a 96 ranger with the 2.3 and a new problem has come up with my A/C. Sometimes the compressor will kick off while im driving or at idle and when it does my idle kicks up. I dont have a tach but it seems to be idling around 2K. Its s manual trans thank ***. When this happens I can tap on the gas and that brings the idle down and usually the compressor comes right back on or I can switch the A/C switch off and then back on and sometimes it will start to work then as well. It also seems to be worse when the fan is on higher speeds like 3 or 4 and happens less when on 1 or 2. Also when I put my A/C on max which would make it recirculate the A/C will sometimes appear to just freeze up. I have checked my pressure for R34 and all seems to be fine. Other than that I have no idea where to start TIA

 

[punisher]

By chance, has the battery been disconnected or have you jump started it recently?

As far as freezing up, do you mean the evap freezes up and stops airflow, or do you have ice on the accumulator/return lines?

 

[Gary Allan]

quote:

---

The idle is raised with the extra load of the AC, and your idle air control valve may be gummy - sticking. When the AC cycles [normal], it therefore won't come back down correctly.

---

This is my first thought. It's overshooting in corrective action.

I couldn't quite integrate what you're seeing as abnormal compressor cycling in your description. I mean what part about the cycling is not normal?? Or rather, when you're sitting there, does it have a routine on off cycle based on fan speed and ambient temp ..regardless of how the idle acts. I don't see the association between the odd idle and any dysfunction of the compressor (then again, I could just be a little dense here

)

 

[mcrn]

ok sorry for getting back so late i just got home from work. thank you everyone for your responses. Ok its not a normal cycle because sometimes the compressor will stay off so long that the air is blowing warm not just cool but warm and will not come back on until I either flip the switch off and then back on or I tap the gas and the idle comes back down and then the compressor comes back on. They are connected because as long as the idle is high the compressor only cycles off not back on again.
And no I have not disconnected the battery or given anyone a jump lately. And by freezing up I mean the evap freezes up and no air outflow not any ice on the lines.
Mechtech a friend of mine was leaning in the same direction as what you are saying. Any chance you know where the idle air control is located? I will look in my haynes manual tonight but they seem to be kind of on the lean side for info when it comes to A/C as I recall.
Thanks everyone and please keep any info coming I live in central Florida A/C is kinda important

 

[mechtech]

I'd recheck the refrigrant amount, since the compressor is off much of the time.
The pressure readings are dependent on outside [couple of inches in front of the condensor] and vent, exit temps., so check your readings off a chart of temp/pressure for the high and low side.

 

[Gary Allan]

It surely could be something directly with the A/C. It can also be some function of the PCM/ECM. My compressor clutch is regulated by the PCM. I would imagine if some condition that tells the PCM to turn off the compressor is present (like falsely detecting too low a MAP output or whatever) that's tied into this idle thingy ....

 

[punisher]

quote:

---

Originally posted by Gary Allan:
It surely could be something directly with the A/C. It can also be some function of the PCM/ECM. My compressor clutch is regulated by the PCM. I would imagine if some condition that tells the PCM to turn off the compressor is present (like falsely detecting too low a MAP output or whatever) that's tied into this idle thingy ....

---

Hence my question about the battery being disconnected, a disconnected battery will erase learned idle settings, causing erratic idle speeds.
The PCM controls AC clutch operation on the Ranger. IF the clutch coil is defective, or there is another problem with clutch engagement the engine still kicks up the IAC to compensate for compressor load and this increases idle speed beyond spec. Freezing evap cores are usually due to a bad cycle switch (yellow switch with two wires downstream from the accumulator)or in rare cases a very worn and binding clutch assembly. I don't think the cycle switches on 96s are adjustable like previous switches.

 

[mcrn]

well thanks everyone for their input. found out my nieghbor across the street from me used to work on A/C's and he said he would look at it. well this morning he took a look at it checked all the pressures and it turns out it was the fan clutch. so the pressure was building up and kicking the compressor off. so that explains why when there was no thermostat this was not happening. well I have another question when he found out it was the clutch fan he said he would help me fix it and he said he would only charge about 25 bucks. well it was a pretty tough job getting in to these small areas was not fun. so when the clutch was replaced he topped it off with a little bit of r34. I gave him 35 bucks he said that was cool but i kinda feel like i should have given a little more i mean we bothed did a lot of the work but it was all his tools and him doing me a favor. what do you guys think it took us about 45 minutes to do. thanks everyone oh and now the A/C is working nice.