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Air Con Issue?

S

Stratos

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Location
Worcs
Car
2008 i-CTDi Tourer
Hi, have noticed over the summer that my air con was not as cold as it used to be so I cleaned the vents and replaced the pollen / cabin filter.
This made no difference other than make the car smell nicer. I also noticed that the air coming out of the passenger vents was slightly cooler than on the drivers side. This was with the settings on 'auto' with the same values.
Now I have not had it regassed or checked in three years so I checked the sight glass and noticed it was just full of bubbles.
Today, I had it regassed and it is now much much colder and the sight glass now shows a constant citrus coloured fluid.

However, my issue now is: on my journey home, I became aware of the air con not working or so I thought? What it is now doing is blowing nice and cold for a couple of minutes and then the system blows warm for a couple of minutes and this just keeps repeating.

Has anyone experienced these symptoms before???
 
I'm not an expert in air con but fredofrog is so when he is on line will be able to help.
The only thing I can think of is your compressor is at fault.
 
As Brett says, the compressor might be faulty, it has an electric clutch which might be slipping.

The other possibility is a perished condenser. The condenser is in front of the engine radiator, and the condenser is sometimes referred to as an aircon radiator. Just as with an engine radiator, a condenser has hundreds of small fins which can become blocked, or detached from the piping, which reduces the cooling efficiency. Generally, with a perished condenser, the efficiency is worse at low road speeds, so the symptom is that the aircon is not as cold at low road speeds, and gets colder at higher road speeds.

There is also an inbuilt diagnostic for the aircon, have a read of this recent thread http://typeaccord.co.uk/forum/topic/22149-air-con/?p=232727

Check to see if any of the sensor values are fluctuating.
 
Thanks for the pointers Freddofrog, I have followed your instructions and have noted the results.

Engine Off: Engine Running:

01 - 28. 01 - 27
02 - 22. 02 - 22
03 - 17. 03 - 15
04 - 75. 04 - 79
05 - 21. 05 - 25
06 - C9. 06 - C9
07 - 10. 07 - 01
08 - 00. 08 - 00
09 - 03. 09 - 61
10 - 25. 10 - 28


I have also noticed (maybe connected) that when my air con button is illuminated, so is the air recirculation at the same time? I am unable to turn the recirculation off without turning the air con off too.
 
When the air con compressor kicks in, the ducts blows icy cold but the compressor does not kick in too often.
And like I mentioned earlier, when I start the car nowadays, the cabin recirculation button comes on with the air con and I cannot turn it off. May explain the musty smell I'm now getting from the ducts even though I have changed the filter and used a cleaner.
 
recirc staying on usually indicates that the system is struggling to get the cabin cold, and it is normal for the compressor to cycle on and off (the duty cycle normally depends on the efficiency of the condenser and the evaporator).

but the gas pressure (sensor 10) is reading very high, which will be why the compressor is remaining off most of the time

the evaporator (sensor 5) is not getting cold and I'm puzzled by the positions of the motorised flaps (sensors 6 and 7)

sensor 9 indicates that the target temperature is set to warm, not cold

Make sure that the system is set to manual mode (not Auto) with A/C ON, and set both target temperatures to LO. Then go into the diagnostic mode and keep the engine running and keep checking all the sensors - look for any that fluctuate up and down, and make notes of any significant changes in any upward or downward trend in any reading

At the moment it could be (in order of most likely) - a perished condenser, a faulty pressure sensor, a faulty evaporator temperature sensor, a faulty in-car temperature sensor, or the magnet valve is stuck in the bypass position.



Note that you can then take the car for a drive in the diagnostic mode, monitor sensor 5 and take the car to a dual-carriageway or motorway where you can drive at a constant 60 or 70 mph. If he value of sensor 5 goes down then it's a perished condenser.
 
Thanks, will take the car out tomorrow and come back with new (up to date) figures.
 
Ok, new figures, on a cooler and wet day are:

01: - 15
02: - 15
03: - 14 - changed to 09 after 5 mins
04: - 78
05: - 03 - changed to 05 after 5 mins
06: - C9
07: - 01
08: - 00
09: - 25
10: - 29


There are a couple of differing numbers there. Hope it makes better sense to you?
 
The sensors are listed here http://typeaccord.co.uk/forum/topic/21770-blowing-hot-and-cold-air/?p=230336

Sensor 10 is the gas pressure in Bar, which seems to be consistently high, so either the sensor is faulty, or there's a blockage (a perished condenser does not lose heat very well, so I think that a perished condenser will simulate a blockage). But I don't think that sensor 9 should read 25 with the target temperatures at LO, so that looks suspicious too.

Set the system to manual mode again with A/C ON and both target temperatures to LO. Then start the car with the system in diagnostic mode and go for a drive and check sensor 5, it should start to go down a while after you have been driving at a constant 60 or 70 mph. If it does not go down, check sensors 9 and 10 as well, and check that the target temperatures are both LO when you come out of diagnostic mode.

If nothing changes much, then it looks like a faulty pressure sensor.
 
Just a thought, before you start the car, set A/C OFF .

Then start the car with the system in diagnostic mode and check sensor 10. If it never drops below 10 Bar then it's a faulty pressure sensor.

If it does drop below 10 Bar, then set A/C ON and see how quickly it climbs, then go for a test drive.
 
freddofrog said:
Just a thought, before you start the car, set A/C OFF .

Then start the car with the system in diagnostic mode and check sensor 10. If it never drops below 10 Bar then it's a faulty pressure sensor.

If it does drop below 10 Bar, then set A/C ON and see how quickly it climbs, then go for a test drive.
Click to expand...

Ok, sorry for the delay!
Have done what you asked (I think) and have recorded the following figures.
These were done on a hot day with the interior of the car pretending to be a sauna.

01 - 31
02 - 26
03 - 47
04 - 83
05 - 29
06 - C9
07 - 01
08 - 00
09 - varied from C7 all the way up to D5 as the car got faster.
10 - 26


I also tried your second suggestion of starting the car with the A/C off and watching sensor 10. The figure was not that much different with a figure of 28 being shown.

Does that help or make it worse??

p:s:
I have just had the airbag recall done and I asked the Honda dealer if they could have a quick look. They only checked the relay which they say was fine.
 
freddofrog said:
Just a thought, before you start the car, set A/C OFF .

Then start the car with the system in diagnostic mode and check sensor 10. If it never drops below 10 Bar then it's a faulty pressure sensor.

If it does drop below 10 Bar, then set A/C ON and see how quickly it climbs, then go for a test drive.
Click to expand...
try this first thing in the morning with the engine cold and un-started, just sensor 10
 
I reckon that that pressure sensor is faulty
If you don't want to pay dealer prices, ask somewhere like Halfords Autocentre for a quote, it's not difficult to do, whoever does it just needs to remove the gas, replace the sensor, then refill with gas ;)
 
Thanks for your help so far,
just so that I know, can the pressure be altered by a re-gas, as in blowing up a tyre, I imagine it would??
The car was re-gassed recently so was wondering if they could have over gassed it.
 
If the system is over-filled with gas, there is a safety valve on the compressor that will blow the gas out.

If the car has been left overnight without the engine running, then the pressure at the sensor should reduce as the gas redistributes itself through the piping, but the fact that sensor 10 is consistently showing a high value implies that there is a fault with the sensor (or the wiring to the sensor). The system will turn the compressor on when the pressure at the sensor is low, but since the sensor is reading high, the system "thinks" that there is enough pressure. In normal operation, the system would cycle the compressor on and off, the compressor would not normally be on all the time, and it would not normally be off most or all of the time.
 
Back again!
Have now replaced the 'a/c pressure sensor' and system all 're-gassed' ready.
I took some readings before starting the car and took some more after the drive home.
The readings look better? and are:

Cold:

01. - 15
02. - 15
03. - 18
04. - 44
05. - 12
06. - C9
07. - 01
08. - 00
09. - 25
10. - 03


Hot:

01. - 18
02. - 15
03. - 04
04. - 66
05 - 03
06. - 64
07. - 66
08. - 00
09. - 37
10. - 08

Figures very different to before, pressure sensor appears to be functioning but cannot tell if the air con is working properly as it's a cool day.
What do you think of th figures Freddofrog??

Thanks for your ***istance so far!
 
That is now working, sensor 5 (the evaporator temperature) has dropped from 12 C to 3 C
You can check that it is working by setting both "target" temperatures to LO and then the cold air will blow and continue to freeze the cabin until the Scotsman, William Lord Kelvin, starts to stop it getting any colder.
 
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