As your evaporator coil cools, the pressure of the refrigerant in your A/C system drops. When the pressure in your system reaches a preset point power to the compressor clutch is switched off. This prevents the evaporator coil temperature from falling below 32*F. If the evaporator coil were to operate below 32*F moisture in the air passing through the coil would freeze and collect as ice on the coil blocking air from passing through the coil. If the evaporator coil becomes blocked with ice all cooling would stop and the A/C becomes worthless. As the evaporator then begins to warm, the refrigerant pressure starts to rise. When this pressure reaches a preset point the compressor clutch reengages and cooling begins once again.
I realize Phoenix has low humidity most of the time, but Honda manufactures USDM cars for use all over the United States and doesn't make special models for dessert use. I remember as a young child my uncle had a Rambler automobile, which had a dessert only selection on the A/C. This selection had nothing to do with the refrigeration cycle but closed the water drain on the evaporator's housing to keep exhaled moisture in the car's cabin.

 

I did this on the Toyota Matrix XRS I used to own. Toyota left the return line uninsulated. Wrapping the line was a fairly common mod back then. It definitely made a big difference on the Matrix, and I would expect it would work on the Fit just as well.

 

Well, someone helpe me identify the return line, and I'll be the first to try the mode out on GE8

 

Just looked up V-Kool on the web:

V-KOOL Automotive Window Coatings Provide Protection from Solar Heat \ Residential Window Film

Definitely going to check this out. Heat soak is a big problem here in AZ, covered parking is usually not available and most parking lot trees here are scrawny (any that get big get wiped out by monsoonal storms). How much do you figure a typical windshield install will run?

 

That was my understanding of how the system operates, too, but the behavior I'm seeing doesn't make sense with this description. There's absolutely no way that the evap coil temp is going below 32 deg. F when this cycling is happening, because it's at its worst right after you start the car when it's been sitting in the sun all day. Even when the compressor clutch is released and its running, you don't see vent temps below 55 deg. F under these conditions, and when the clutch is engaged and the compressor is off, the temps go to 80 deg. F or more. It also seems like the ECU is engaging the clutch under any moderate acceleration, too. Many cars (e.g. my M3) have a compressor cut-out that happens when you use wide-open-throttle acceleration, but in the Fit, the cut-out will happen at half-throttle accelerations.

Nobody expects the A/C to cool to 40 deg. F vent temps within 1 minute of startup after sitting outside all day in 100+ temps, but I do expect the compressor to keep running until the vent temps drop to a reasonable level. I'll see if I can get a service manual to look at to see what it says about the cycling.

 

Pbanders asked if there is anything else that can be done.....

A previous article had a reference to a Ford Taurus mod where a switchable resistor was placed in series with the evaporator themistor. This thermistor is meant to sense when the evaporator coil has excessive moisture (strictly temperature driven) and keep ice from forming and freezing up. You won't hurt anything if it does just lose cooling ...l the ice thaws (with the hot air blowing over it). This is mainly a concern for high humidity conditions. For Phoenix, I am betting that yours is a very low humidity envoronment and this mod would give you a lot of relief in eliminating the cycle time with no risk.

The Fit's system appears to be similar to the Taurus. An internet search stated that "all automotive A/C thermistor applications are NTC" (negative temperature coefficient). The trick is to determine the correct resistor values because there are a variety of different thermistors out there.

Although I find my A/C so far to be adequate in Ga, I have noticed every once in a while the warm air. Whe I get some spare time I plan to purchase an extra thermistor from Honda (about $15) and put it in a ice bath and measure the resistance. That way you can figure a simple "resistors in parallel to bias the temperature reading up a few degrees and should reduce the cycling. In the case of Phoenix (with low humidity and high temps), I would consider choosing a value to essentially defeating the cycling without sending an error code to the control unit thinking that it failed.

I am thinking that a 1/8 or 1/4 watt resistor with the leads tucked into the connector across the terminals of the thermistor would be all you would have to do for the simplest version of this mod raising the freezing setpoint up just a few degrees of margin. Otherwise a switch with a resistor across the terminals would allow you to switch it in and out for high demand or low humidity conditions. Of course if you demanded the full variety described in the Taurus mod you could put in the 9 position switch with a variety of incremental resistor values but I think that this is overkill.

Dave

 

i have the same problem, IT SUCKS

 

Turned out my fresh air/recirculate switch was broken, they fixed it with the oil change under warranty.

Now my vents are engaging recirculate properly and I have the feeling they fixed something else because my vents are getting colder than ever, for the first time there was condensation forming around them today and it's 87F outside (feels like 90F).

 

Passenger side the bare aluminum hose that's supposed to be cold with the A/C on.

 

now that summer is here (IN NY)i hope this thread gets more attn

 

I usually select the closed position on my A/C control to help it cool down quicker. In this position it is common on a hot humid day for the evaporator to freeze up and quit blowing air..... I forgot to change the position to open yesterday in 102 degree temperature and realized what I had done and turned off the A/C but left the fan on high and switched to open mode... Within a minute it was blowing very cold air and as the temperature got warmer I turned the A/C on again, and drove the remaining 75 miles cool and comfortable.... My A/C always freezes up on the closed recirculative setting.

 

I think 108 is predicted for today, . I'm getting OK results doing the following when I get in the car to come home from work:

1. Start car, turn blower on high, A/C on, fresh air intake
2. Roll front windows down and remove padded/reflectorized window shade (hot as you know where when you roll it up).
3. Drive for 30 seconds and roll windows up
4. Avoid hard acceleration for first few minutes to prevent compressor cycling
5. After interior temp drops a bit (~2 to 3 minutes), flip to recirc mode

I'm on the freeway about 5 minutes in, once I get there, the vent temps drop to a reasonable level and the compressor cycling decreases or goes away.

 

from this diagram, which hose?

http://www.hondapartsnow.com/part-im...117/470123.png

 

10 & 15 (top) the bare aluminum part

 

Well, I cheked those tubes... there is definitely insulation on them, about 85% covered. There is a small portion of the tube exposed (and it was sort of cold to the touch) .... doesn't seem like insulating that small piece would make a big difference. I think I'll pass.

 

Certainly the Honda A/C is probably the worst, but Hondas are built for economy, and they do a good job, as I can't argue with a 35mpg commute. It used to be that a/c was not even an option on cars as small as this, so some a/c is better than none at all. Everything is a trade off, that is why the performance, comfort and handling are bad. I am also in Phoenix and it has not started to get real hot - yet! When it does I'll drive my other regular car, and won't mind paying for the extra gas involved.

 

What was the outlet temps from the center vent after 'airing out the car' and then after closing windows and using recirc for 5 minutes. Thats the true measure how good your A/C is.

 

Excuse me? You can't be talking about the sport model, as the performance and handling are easily the best in class (micro cars) with the exception of the Mini Cooper S. Maybe you have the base model Fit?

As far as comfort I'll give you that one. The problem is the damn seats. The seats need more lumbar support and they need to do something about the active headrests which force your head forward in an unnatural position. Since I plan on owning the car for a very long time I'm going to look into the cost of seat replacement.

As far as the A/C, it is what is and I've come to accept it. It's a small car, with a small engine, lots of glass, and lots of black heat absorbing plastic, so it's always going to be a struggle to keep the car cool on 100 degree plus days. Using a sunshade and getting your windows tinted as dark as possible are your only options for helping the A/C do its job. My car is white and that probably helps a little as opposed to a black car, but it's really the sunshade and the window tint that will help the most.

Finally, like you said, cars this small didn't even used to come with A/C so complaining about it is pretty pointless. Honda is not going to "fix" the A/C because there is nothing wrong with it, and I think people here are expecting more out of it than it's capable of.

 

You have summed it all up quite thoroughly.... The driving position just doesn't work for the average sized American of European lineage and the hardest thing for me to live with. .... The huge wind shield and expansive black plastic dash is the biggest source of heat transfer as far as I can tell... .. The A/C will run you out even on the warmest nights.... If I spend a lot of time outdoors in the long hot Texas summer and become acclimated to the heat, I find the A/C to be a welcome relief and very satisfactory.

 

Very well, went ahead and tested this... I put some rubber insulation (from Lowes) to covder the 2 largest aluminum segments... the third/last segment is rather short, and towards the back -- hard to reach.

I should have done some testing BEFORE and after, but forgot Anyhow, everything is nice and cold, but I notice is that the compressor is not cycling much... in fact I can only hear it cycle if I set the fan on position 1. Other positions (2,3,4) don't trigger a cycle at all. Im in neutral, in garage/shade, engine running.

So this get me to thinking... could this be having some adverse effect on the A/C system? Is there some temp sensor I may be affecting by covering the pipes?