Air conditioning revisited
 

So just today I started to notice what some others have posted about with the "surging" air conditioning. Seems like it runs very cold for a few seconds then warm then cold, etc.

Anyone find out anything about this? Mine wasn't doing this until today so just wondering if anyone has talked to a service department about it and if it is normal (or why it happens).

Sitting at idle it works fine. Stop and go traffic seems to cause it to start doing the surging.

I am thinking it is something to do with the 65% cutoff. Maybe it is misinterpreting something and keeps cycling.

It still keeps me from getting hot, but still is irritating.

I smell a recall.

I drove an automatic today. Fan works great but the A/C temp was luke warm. I have heard of occaisions where the factory, or port, correct me if Im wrong, will "overfill" the A/C system. (if overfilled A/C does not work properly i.e. we get very little or no cool air) As for the surging, I did not find it happening on the car we drove. It was an automatic with three of us in the car. A/C Luke warm.

I dove 125 miles today in 80-95 degree temps. 2 hours of that was in stop and go L.A freeway driving. The a/c worked flawlessly. My only complaint is that the the jump from fan speed 1 to 2 is too much. My Acura had an infinately variable one.

There is something up with the AC. Not just coldness, but weird blow off blow on, cold-freezin-normal air, crisp then humid suddenly.

It sounds like the HVAC controls are cycling the A/C compressor on an "as needed" basis (not that uncommon, my 1997 Jeep Wrangler did this) but that something is causing the system to wait too long before reengaging the compressor clutch.

The way it worked on my Wrangler was that the compressor would kick in and operate until the system reached a particular pressure, then shut off. This meant that on cooler (e.g. 70°F) days you could hear the compressor cycle on and off quite frequently and on hotter days (e.g. 90°F+) it would remain on constantly.

It shounds like the controls are leaving the compressor off too long, resulting in warm air being blown out before the compressor kicks back in, resulting in the "max cold" air followed by warmer, more humid air.

Just a theory - although I know an air handling expert, I do not profess to be one. :)

Yep... same here. Been driving for 3 days now in about 95 degree Texas heat. No problems with the AC for me. Blows very cold air, and is very strong. Have not noticed any problem with the AC blowing warm air at any time.

i've noticed it kinda follows the revs, in really bad stop and go traffic it warms up when i'm at idle...then gets quite frosty once i break 3k rpm. it is kinda weird but i never use a/c unless i have passengers who complain about cabin heat anyhoo =p

That's what makes me wonder if it's compressor cycling as I mentioned with my Jeep Wrangler. 95°F is hot enough that the system would keep the compressor enabled all the time, but Southern California has been in the 75° - 80° range all week, which is much cooler and might cause the system to cycle the compressor on and off causing the variation in air temperature from the vents...

Air Conditioning performance
 

After 2 weeks in heavy traffic and 90 degree temp I find the AC to work well enough. It definitely surges in temp during idle more than I expect from Mazda.

My 2nd gen. RX-7 and '93 Miata never displayed the same behavior as my "8".

I'm more concerned with the poor gas mileage.

400 miles so far and I probably drive too fast.

When it occurs (which isn't all the time) it starts cycling cold, warm, cold, warm about every 5 seconds or so.

But doesn't happen all the time. Wierd. I will update more info as I have it.

I've tried driving a few times according to the manual, and it would have you shifting at about 3000rpm! I find this hard to do because the engine is so quiet, the engine revs up so fast, and the visual cue of shifting when the tach needle is at 8o'clock (am!) is hard to comply with.

Well I am in the vehicle air conditioning business and I have
this same problem with mine. Took a quick look at it yesterday.
Good news it that the system is diffenately not undersized.
There is also not an issue with the refrigerant charge level
(too much or not enough). The compressor appears to cycle
on both a low pressure switch which appears to be ok and also
a signal from a evaporator temp sensor or the engine ecu.
At times the compressor does not run long enough. I need
access to the factory A/C control wiring diagram to find the
answer. It should be an easy upgrade campain for Mazda to
fix this issue.

Rock on Zoom49. Good to hear someone in the know has taken a look. Be sure to let us know whatever you find out as diagrams become available.

Hmm Had mine a week now It has been around 94 degrees with high humidity in FL . The AC compressor seems to kick in about 20 sec after starting and really klunks. Have also noticed an air fan speed changing. Air seems to work fine but takes a while to cool the black interior after being parked in the sun. I also leave it on max cool.

ALso, according to the technical CD the AC cuts off automatically when around 60 % of the throttle is opened. THat MAY account for the air temp in stop and go.

On mine the vent air cools down to 45 degrees on #2 fan setting, then the compressor cycles off and comes back when temp above 50. That is when it feels luke warm coming out. It has been over 110 degrees here. It has no problelm cooling vent temp down to 45 on ither fresh air or recirculate. It is the compressor cycling off too quickly.

For posterity, I'll post that my RX-8 was doing this when I was on the way home from work....about 85 outside, and I had to throw the fan on setting 4 just to remain comfortable. I had it blowing directly on my face, and could feel it turn on, off, on, off, etc. in cycles. I was going to call Mazda and tell them it was faulty...but it looks like it is happening to a lot of you. Let's all call our dealers so they know the issue exists.

To ZOOM49
 

With the horsepower fiasco, the air conditioning isses seems almost forgotten. Do you (ZOOM49) have any additional thoughts or information?

As I indicated earlier on mine the probled is not related to refrigerant level (tried adding and removing no benifit) The
ECU of other device appears to be allowing the clutch to cycle off before the proper vent temp is achieved. Also it is NOT related to the 65% throttle issue as it also happens on mine at idle and
very light throttle on highway. I have not been able to get a
wiring schematic yet for the A/C. I will be able to help when I get this. I have contacted my dealer about getting this with no response. Ibfubar has not heard of a TSB on this issue. Will post as soon as I find out.

As I mentioned earlier, I suspect there are high and low pressure switches in the A/C system that trigger the compressor to turn on and off, cycling the compressor. This is normal for many HVAC systems, the question is why the low pressure switch is allowing things to get to the point where minimally conditioned outside air is felt. Perhaps it's a bug in the ECU software or an improper low pressure level was selected.

Regardless, until someone here gets to read a service manual we won't know for sure...

I think there may be a rumor of a new TSB, can we get anyone to verify?

AC satisfaction
 

I read a lot on this board that many are unhappy with the Air Condition performance. I live in Phoenix and the AC is about on par with other vehicles I have been in. The black interior sucks up alot of heat it and would have been nice to see a light grey/silver interior option. It is much beter than riding in a SUV they don't cool down till Oct.

I'm tinting next week to offset my black interior's Sun grabbing magnet. That should help dramatically.

Yea, I'm not very satisfied with the AC, I think because the cabin gets so hot from a transmission that the AC has to work harder. But AC is not a big concern for me cuz it just slows down the car.

Mine is just like lefuton stated. It only coold great when I bring the engine revs up off idle. I have not had the amplifer replaced yet as it is in that range, so hope that fixes it. Didn't check the pully ratio as Mazda could have the compresser turning slower than most cars or the RX7 since this engine goes to 9000 rpm.