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Magnesium 07-25-2003 07:49 PM

Air Conditioner cycling!!! Fix it!
 
2nd day of driving the nice 8 around. It was a little hotter day today so I needed to turn on some air cruising around town.

The A/C seems to work fine for a little while, then starts cycling cold/warm/cold. It cycles so fast that it keeps me from getting hot, it just doesn't cool me down like I am used to.

Nobody here can tell me that this is going to be normal because sometimes it is fine, sometimes it's not.

I have a feeling that it has something to do with the 65% cutoff for power, but shouldn't be this sensitive being I am still driving like grandma during the breakin period...

Any suggestions?

XK4 07-25-2003 08:59 PM

The RX-8's A/C seems to be sub-par, at best. Tinting your windows will help a lot. I've been driving around the D/FW area for the last four days with the A/C fan set to "2" and have been quite comfortable. Prior to tinting I needed "3" or "4" on the fan.


Dave

Magnesium 07-25-2003 11:50 PM

I am thinking that maybe my A/C is undercharged or overcharged. Dealer here I come...

sferrett 08-05-2003 10:16 PM

So I'm interested if the trip to the dealer yielded any results on the quick a/c cycling. I picked up my black sports '8 a couple of weekends ago and one thing I've noticed is that the a/c seems to spend about as much time blowing tepid air as it does cold air...

Curious if the dealer did anything and if it resolved it or not.

Cheers,
Simon.

dcfc3s 08-06-2003 03:35 PM

I had a thought about this the other day...

Part of the problem might be the AC working *too* well. All auto AC systems have temp senders in the evaporator (the "radiator" under the dash that cold freon flows through and blower air goes through - it removes heat from the air). If the evaporator gets too cold, frost will form. This can lead to a sticking expansion valve, frost blocking the fins of the evaporator, etc. So, a temp probe is in there to cut the AC compressor off until the evaporator warms up, then the AC compressor kicks back on.

If the system works too well, it's hovering around the cutoff temperature and cycling constantly. It could also be a hypersensitive temp sensor in the evaporator itself.

My wife's '90 convertible RX-7 has VERY good working and super cold AC, and I have noticed it cycling every now and again. I don't know how pronounced the problem is on the '8. Part of the deal too is the RX-8 uses R-134a as a refrigerant (the ozone-friendly stuff) - only a few of the last RX-7's had 134a. Don't know if that makes a difference or not - an AC system has to be designed around the refrigerant.

Dale

brownchiro 08-06-2003 04:57 PM

Mine works great. I never have to use it above 1 or 2 fan speed. It is 105 here today. You must keep the AC on recirculate; never on fresh air or you will get hot and cold blasts.

91vert 08-06-2003 08:46 PM

You should not be getting hot and cold blasts even if the recirc is not on. I agree that something is major wrong with the way they have the compressor setup to cycle. It is coming on a few seconds too late in between cycles, and during that time you get a few seconds of warm air.

I think the A/C in my car absolutely sucks.....and it hasn't even been that hot and humid here in St. Louis over the past week since I have picked it up.

I'm planning on making an appointment to get it in to the dealership to have it checked out as soon as I get some time. I'm sure they will tell me it is operating to spec, but you never know. Maybe they will find something wrong.

msrecant 08-06-2003 09:29 PM

I agree the AC system seems weak, at least compared to other cars I have driven recently (626, Saturn L Series and my Miata) all of which I would characterize as having acceptable but not outstanding AC. When used in fresh-air mode the RX-8 does not seem to cool well at all.

As noted above, I have also seen that using RECIRC fixes the problem. It provides plenty of cool in that mode which implies that it is not a flaw like improper charging.

Hopefully this is a Version 1.0 bug that will be fixed shortly.

Wing 08-07-2003 05:56 PM

Mine works WAY better than in my Tiburon. It's COLD on fan 1 and right as soon as I start it almost. No hot cycle. It was 30 C today and sunny no problems.

Shamus 08-08-2003 12:33 PM

In the 2 test drives I've done on very hot days here the A/C has been flawless AS LONG AS the air is not being pulled from the outside. It has to be recirculating inside air only. This is nothing different than any other car I've owned though. To get the coldest air, just recirculate the inside only.

msrecant 08-08-2003 02:41 PM


Originally posted by Shamus
In the 2 test drives I've done on very hot days here the A/C has been flawless AS LONG AS the air is not being pulled from the outside. It has to be recirculating inside air only. This is nothing different than any other car I've owned though. To get the coldest air, just recirculate the inside only.
You miss the point. The AC really is terrible when it is NOT on recirc. Last night it was only 80 degrees outside and the AC, in fresh mode, continually cycled every 20-30 seconds from very cold to warm, which did not do the job of keeping the interrior reasonably cool. Not comfey ... you need to try it to believe it.

eccles 08-08-2003 02:54 PM


Originally posted by msrecant
The AC really is terrible when it is NOT on recirc. Last night it was only 80 degrees outside and the AC, in fresh mode, continually cycled every 20-30 seconds from very cold to warm, which did not do the job of keeping the interrior reasonably cool. Not comfey ... you need to try it to believe it.
I have tried it, and I only partly believe it. :)

When I run mine on Fresh, I occasionally notice the cycling. It never gets warm but I notice it starting to get less cool, and just as I notice it, it kicks back in and blows cold again. But it doesn't happen anywhere near all the time, and it's happened infrequently enough that I have yet to determine if there's a common thread between the times it does happen, except that it's always in Fresh mode, never Recirc.

It's obviously not caused by excess demand, beacuse it's been 108 degrees here the last couple of days, and my AC has performed flawlessly.

msrecant 08-08-2003 03:31 PM


Originally posted by eccles
I have tried it, and I only partly believe it. :)
Since my AC works fine in RECIRC I have had a tendency to leave it there. It has performed poorly on FRESH the times I have tried it.

I will try living with FRESH for a couple of days and see if the poor performance is consistent or not. My plan is to complain to the dealer when I take the car in for its first service. This will let me complain more intelligently (oxymoron?).

8_wannabe 08-08-2003 04:37 PM

Same problem here, I've had the car about 3 weeks. Always on recirc, always turned to the coolest temp, but it cycles warm and cool air. It won't blow cool long enough to really cool down the cabin. don't tell me I'm operating the A/C wrong; I know how to set a/c. those of you not experiencing the problem: Good for you, you got lucky somehow. But some of us have got bum a/c units. Can over/under charging with coolant cause this? Has anyone yet had a dealer render an opinion?

pelucidor 08-11-2003 01:40 PM

On three test drives of different RX-8s I thought the AC was OK in Houston weather. Actually I didn't notice it because I was more interested with how the car drove.

Now that I own an RX-8 I will say that the AC is buggy for sure. On RECIRCULATE mode it is poor, on FRESH AIR mode it is even worse - I only use recirc mode. On recirc I find speed 1 is too faint to feel at all (face vents only), at speed 2 it is too strong and the cold air cuts in and out continously every few seconds (gentle driving at 3000 rpm). Temp is always left at lowest setting. Even my 120k mile '91 Integra had better AC behavior, and all 5 of my new cars since then have been vastly better.

After I got my Huper Optik tint things are better (double the heat rejection of other tints) as I can leave it at speed 1 after the car is cooled down a bit. But it is a major flaw for those in hot climates like Texas.

rx8racer 08-11-2003 02:54 PM

Air conditioner pump cycling
 
I just talked to my dealer about the AC cycling problem. He called the Mazda "tech line" and was told that this is "normal." The car is programmed to cycle the AC on and off. He said that Mazda acknoledged that they have received comments about it but they are not getting "complaints." They did not give a reason for this. (improve gas mileage I'm guessing) He also commented that when set to fresh air, it will cycle more than when set to recirculate.

Mazda would be able to fix this with a quick update to the ECU if they wanted. If everyone starts complaining about it, maybe they will fix it. I think it is stupid to run the AC at 50% when you are sweating to death! I'm considering hard wiring my own switch to override the ecu control.

msrecant 08-11-2003 04:03 PM

Re: Air conditioner pump cycling
 

Originally posted by rx8racer
If everyone starts complaining about it, maybe they will fix it.
Agreed! I have a service appointment at which point I will lodge a "complaint".

rx8racer 08-12-2003 08:58 AM

AC testing last night
 
I did a little experiment with my AC last night. It was annoying me to death listening to the clutch kick in and out while I had the car idling with the air on. Here was the test:
I started the car and let it idle. I turned on the AC with fan speed 1 and fresh air on. The clutch kicked in for about 30-45 seconds then it continuously cycled on and off about every 7 or 8 seconds. This is very annoying and would be very hard on the clutch. It also doesn't cool nearly as well as it could. Does everyone experience similar results when idling? I think it does the same thing while cruising but it's not as niticable. I also tried reving to 2-3000 rpm and the same thing happens.

Zoom49 08-12-2003 09:06 AM

Yes the clutch cycles even at idle with the interior temp still hot.
This is the reason I dont think it is related to the 65% throttle.
I also connected an A/C guage set and it does not appear to cycle on any pressure control. Tried adding and reducing refrigerant charge with no effect. I believe it is controlled by the ECU or a temp sensor on the coil.

Len 08-12-2003 09:11 AM

Re: AC testing last night
 
That's exactly what the AC did in my '92 Prelude too. That clutch lasted for > 10 years, so hopefully the RX-8 one will too. The cooling in my RX-8 seems at least a bit more effective than the Prelude.

rx8racer 08-12-2003 10:47 PM

appointment
 
I made an appointment with the dealer to check it out this week. I want to get my "complaint" logged so hopefully Mazda will fix it someday. I am also going to log my complaint about a loss of power above 6000 rpm and see if the tech can give an explanation.

Wing 08-24-2003 06:10 PM

I finally noticed this, I was just cruising and I felt my arm get less cold, not hot just less cold.

This is the first time I use the AC on a day that really didn't warrant it. I believe I had it set to fresh air.

It was somewhat annoying.

pelucidor 08-24-2003 11:50 PM

I will definitely lodge a complaint about the AC - it is so much worse than on any other car I've ever had (Lexus IS300, Acura MDX, Lexus RX300, Jeep Grand Cherokee, Acura Integra, Toyota 4 Runner, Honda Prelude - even cars 10 years old). Heck - it is even worse than Chevy Cavaliers, Pontiac Grand Ams, Hyundais, Mustangs, Sebrings etc I have rented. I only use recirc and it continuously cuts in and out even whilst driving around fairly gently.

jonalan 08-25-2003 01:32 PM


Originally posted by pelucidor
I will definitely lodge a complaint about the AC - it is so much worse than on any other car I've ever had (Lexus IS300, Acura MDX, Lexus RX300, Jeep Grand Cherokee, Acura Integra, Toyota 4 Runner, Honda Prelude - even cars 10 years old). Heck - it is even worse than Chevy Cavaliers, Pontiac Grand Ams, Hyundais, Mustangs, Sebrings etc I have rented. I only use recirc and it continuously cuts in and out even whilst driving around fairly gently.
I noticed there is no mention of any Mazda vehicles.

As a previous owner of several Mazdas, I can say that they have always lacked in the A/C department. IMO - not that this helps or anything.

Spin9k 08-25-2003 02:39 PM

Does RX-8 Have ECONO AIR?
 
Here is YAT (yet another theory). I think mine seems to match the symptoms we are experiencing almost to the letter, however.

1. FIRST PROBLEM - OUTSIDE air coming into the car through the vents is HOT. With out the air conditioning on, the air with blower on is way hotter than ambient temp. SOMETHING in the engine passthrough is HEATING the air and it definitely needs more insulation along the way.

2. I belive the RX-8 has what is other cars is called ECONO A/C vs FULL A/C. I have another car w/switch for ECONO vs FULL and the manual says the following:

ECONO POSITION - Use this position when the humidity is low. It is economical as the air conditioner compressor OPERATES ONLY WHEN NECESSARY (caps mine).

FULL A/C - Effective when the humidity is high or when it is very hot. The air conditioner compressor OPERATES CONSTANTLY FOR ADDITIONAL COOLING. (caps mine)

NOTE: I have never been happy with the ECONO mode in the car, always use FULL, as it does what the 8 does, even though the outside air is not superheated in THAT car 1st.

SO when the COMBINATION of an air conditioner that is PERMANENTLY in ECONO MODE (cycling compressor) and HEATED AIR from the ENGINE compartment being used when NOT IN RECIRCULATE, the result is cool, then not cool *almost immediately* as the compressor coils 'lose their cool' due to the hot air. Then the air comes on again... A VICIOUS CYCLING so to speak!!

Why ECONO A/C in our car? Well economy is at issue it appears, maybe a little too much. And so they tried to compensate in any little way possible.

Any one agree or see a problem with this hypothesis??

PS If we could get a shop manual we may find the answer to whether this is in fact... FACT!

MPG > HP 09-11-2003 02:21 AM

Poor A/C
 
Was sitting in my driveway after driving home from the dealer. Just reading the manual while waiting for the garage floor to dry out after cleaning the garage up a bit. Noticed it getting a little warm, so turned up the A/C. Few minutes and not cold, like my other RX's, so turned up to "full freeze". Still not cold, even tho amb temp was only 64 F. If it were that cool outside with my other RX's, I would have been freezing after just a few minutes.

Took it to the dealer the next morning. Response: "Couldn't duplicate the problem and temp probe indicates 47 F, per spec" Was told I had "jumped the gun" and should give the "intelligent environmental program" a chance. Well it's been a week now and still no good cooling even though daytime highs have dropped from mid-90s to low 80's.

Not disasterous, as the car is still "livable" when driving alone, but you should hear my passengers complain when I take them out for a test spin!

Anyone else taken their cars in for this problem? Did they do anything about it?

Otherwise, this car is the best street driving RX, yet! All the best features of the past refined. Don't care much about the HP issue, but am concerned about the MPG complaints I've been hearing (but that's a different thread).

LTAGFERN 09-11-2003 09:44 AM

Relative to A/C operation, I've been puzzled by the cloud of 'frost' that is emitted from my '8's center vents (perhaps ALL vents, but MORE VISIBLE from the center vents). As the A/C cycles into its 'cool-it-down' stage, a cloud of frosty air is blown from the vents. A/C then cycles 'off', and 'cloud' disappears. A/C then cycles 'on', return of the frosty cloud.

For whatever reasons, I've seemed to be aware of this happening only occasionally in the mornings while driving the freeway. Using the FRESH AIR/OUTSIDE mode.

I recall . . from YEARS ago . . my father had an 'under-the-dash' A/C unit added to his Rambler station wagon, and the unit control knobs could be manipulated so that frosty air could be blown from the unit. While riding 'shotgun' during those years, I developed the ability to irritate my father and other passengers by being able to quickly/anytime create a cloud of frosty cold air. I remember this condition (frosty air) as NOT being a 'good thing', because it was difficult to maintain visible frosty air without the A/C unit freezing up . . which meant NO A/C until the unit thawed.

So, I've been pondering if my '8's A/C is actually working . . too well . . so that it is close to that 'freeze-up' position or, perhaps, IS freezing up.

It's a puzzler!

8_wannabe 09-11-2003 10:09 AM

Re: Does RX-8 Have ECONO AIR?
 

Originally posted by Spin9k
I belive the RX-8 has what is other cars is called ECONO A/C vs FULL A/C. I have another car w/switch for ECONO vs FULL.
What makes you think the '8 has this? And how can we switch between the two modes?

eccles 09-11-2003 11:15 AM


Originally posted by LTAGFERN
Relative to A/C operation, I've been puzzled by the cloud of 'frost' that is emitted from my '8's center vents (perhaps ALL vents, but MORE VISIBLE from the center vents). As the A/C cycles into its 'cool-it-down' stage, a cloud of frosty air is blown from the vents. A/C then cycles 'off', and 'cloud' disappears. A/C then cycles 'on', return of the frosty cloud.

For whatever reasons, I've seemed to be aware of this happening only occasionally in the mornings while driving the freeway. Using the FRESH AIR/OUTSIDE mode.

It's a puzzler!

No, it's condensation. The humid outside air is being rapidly cooled by the A/C, and the water vapor is condensing into a small cloud. Perfectly normal, but it will only happen when the humidity is up, which probably explains why you only see it in the morning.

eccles 09-11-2003 11:21 AM

Re: Re: Does RX-8 Have ECONO AIR?
 

Originally posted by 8_wannabe
What makes you think the '8 has this? And how can we switch between the two modes?
The RX-8 certainly has this in some markets. If you look carefully at the red LCD display, you can see several indicators that are unused on US-market cars. The fan speed display has already been discussed in other threads, but if you look closely you can see that there's also an unused ECO indicator alongside the AC indicator (inside the same box, which explains why AC isn't centered in the box).

Whether our AC's are actually operating in economy mode, I cannot say, but it seems that they're certainly capable of doing so with the right control inputs.

1fine8 09-11-2003 12:32 PM

Mazda has told me a PCM (power control module) is being developed to correct the a/c problem. Suppose to be out in 3-5 weeks.

mikeb 09-11-2003 12:53 PM

do we get the pcm free of charge

1fine8 09-11-2003 02:18 PM

I told Mazda to fix my air conditioner of else they can have it back. I assume they will correct all air conditioners of those owners who are dissatisfied and who voice their concerns.

I will still be dissatisfied if Mazda says "specs are only 47 degrees" as posted above. My other vehicles can cool down in the 37-38 degree range.

flatso 05-11-2004 01:40 PM

ok so I finally used my AC today and noticed the cycling mentioned but I am a bit confused, mine seems to blow cool, less cool, cool over and over say every 6 seconds going from one to the other, is this normal? Are the defective ones blowing cool, warm, cool only? If you got the ac amplifier what happens now to the AC?

MPG > HP 05-11-2004 10:09 PM

I just got my dealer 15k mile service survey and was sure to note that the dealer failed to address my complaints (brought into dealer on day 0.5) about a/c cycling. I believe it's just an economy move as all my other RX-7s had so much cooling that, even on hot days, I had to use defroster mode with low fan to limit the amount of cold air entering the cabin.

flatso 05-12-2004 05:06 AM


Originally posted by MPG > HP
I just got my dealer 15k mile service survey and was sure to note that the dealer failed to address my complaints (brought into dealer on day 0.5) about a/c cycling. I believe it's just an economy move as all my other RX-7s had so much cooling that, even on hot days, I had to use defroster mode with low fan to limit the amount of cold air entering the cabin.

you might want to bring the TSB in now that it is a recognized problem they may be more willing to fix it.

itsallaboutgary 05-13-2004 06:44 PM

Well here it is guys...the solution to the a/c problem =)

http://www.finishlineperformance.com...07-002-04.html

tyrchon 05-13-2004 07:57 PM

Yeah, now I just have to get the dealership to agree to do the work, they have been a pain to get to do anything.

stickman 05-13-2004 09:13 PM

I had same symptoms as already described, cold then barely cool. First time dealer said it cooled to spec. I took it in again on a 90 degree day and told the dealer that the ac sucked for a $30,000 car and I had rented econo box cars at airports that cooled better. I said no way this is "normal" and to not even think about returning the car to me unchanged. I also gave them the tsb even though mine is outside the vin range. Turns out it was over-charged and got too cold which then resulted in frozen evaporator and shut down until evaporator could warm up. Car has been great since they adjusted the charge.

msrecant 05-13-2004 09:28 PM

Thanks for the tip STICKMAN. Also a good reminder that not every problem is a design flaw.

91vert 05-18-2004 07:55 PM

I got the new A/C Amplifier installed today (supposedly), and the A/C is not much better, if at all. It was only 82 degrees, sunny, and a little humid when I picked the car up from the dealership. I could still feel the cold - warm - cold - warm cycling, but it might have been a little bit better than it had been. I haven't driven it enough in hot weather yet to know for sure.

What is stumping me.......is I'm wondering if they really did replace the part like they were supposed to? The reason I wonder is because the box is in plain view upon looking up under the driver's side footwell, and there was a little dust on it like it might have been there for a while. It did not look like the screws holding it down had ever had a screwdriver in them to remove them, and the wiring harness clip that holds the harness to the hole in the amplifier housing did not look like anything had been used on it to push in the little tabs to pop it out. I dismounted it to look at the part number on it, and noticed in the TSB that the part number remained the same as the original defective part, which is kind of odd. It did not even have a label with the actual Mazda part number on it. There was Denso sticker on it that had the 540 number on which jives with the end of the Mazda part number. Why would they not have a different part number if the "guts" of the amplifier are different??

Maybe they did replace it, but I just don't trust dealerships to be honest.....especially when it comes to replacing parts like this that may be totally unnoticable to a customer.

I would suggest that if you have this part replaced that you make some descriptive mark of some kind on the part then check it when you get the car back to see if they really did swap the part.

Maybe I'm just being paranoid, but I expected a noticeable difference in the functionality of the A/C, and it just not there.


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