Member Since: 11 Jun 2013
Location: Berks
Posts: 166
Here are my figures
At cold start up this evening
Then pull the plug on the high pressure switch after car has warmed up slightly
Plug back in and pressure rising but still not up to the max 1600kPa I saw earlier. Similar behaviour though in that pulling the plug causes the compressor to kick in short term but then switch off again and pressure drops.
Disco3 project
26th Apr 2017 8:31 pm
JMack
Member Since: 02 Aug 2014
Location: Edinburgh
Posts: 1517
Strange your IID showing ignition off, with engine running!
Anyway, I'd suggest running the engine and heating the car up to mid 20's or higher, with the Econ button pressed so no compressor amps.
Then max cooling and Econ off and log the readings in a graph. Pressure, Amps, Evap and Cabin temps.
No revving engine (made no difference to mine) and log it for 10 minutes or so.
26th Apr 2017 9:28 pm
dreynolds10
Member Since: 11 Jun 2013
Location: Berks
Posts: 166
I'll give it a go and post results but I think I can predict what they will be.
i.e. constant pressure around 3.8bar - 4.0bar and all temps relevant to current outside temps.
But i'll give it a go and see what happens.
Thanks for continued ideas Disco3 project
26th Apr 2017 9:59 pm
dreynolds10
Member Since: 11 Jun 2013
Location: Berks
Posts: 166
I took some additional readings and had a play with the aircon whilst out driving today and I could get the AC to work albeit for a short period of time if I followed the following procedure whilst driving.
Econ On (so compressor off and no current)
Temp Gauges down low
wait for Evap temp to drop (I was monitoring IID whilst driving)
Turn Econ on
Low and behold the AC would kick in and pressure would rise
I then turn up temp gauges to warm - cabin warms
I then turn back down to max cold and pressure on Compressor drops and no cold air
When I repeated the cycle I could get the AC to come on (i.e. if I then turned Eco on and waited for Evap to drop before turning back on)
I got home and took some more readings on the drive so I could snap the images
First pic was taken when I first switched the engine on after having some lunch -
Note the high pressure to start but then pressure collapses and current rises
Click image to enlarge
I then switched Econ on so that there was Zero current to the compressor
Note pressure drops and settles around 500 (actually settled at 475)
Click image to enlarge
I then run the blowers for a while and then switch Econ back off - So there is current to the compressor, temp on lowest, blowers on max.
Note the Pressure rises to peak of 20Bar
Current then continues to rise from 150A up to 242A
As the Current rises the pressure starts to drop
As the pressure drops the blowers turn from ice to blowing warm ambient air
Click image to enlarge
I repeated this exercise for a cpl of cycles but then it stopped working and no matter what I tried I couldn't get the compressor to come back on.
At this point the pressure settled at around 475KPa.
Evap temp would rise to the same as the interior temp
Comp current would rise and top out at 242A
The current on the Compressor seems high but I don't really know what that should be.
I am thinking that maybe the control valve on the compressor is playing up. Sometimes working if it gets a call to be switched on and off. Then sometimes just sticking and not operating at all.
Any other ideas?
CheersDisco3 project
28th Apr 2017 3:13 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
Is the viscous cooling fan driving and shifting air?
28th Apr 2017 7:04 pm
yaxman
Member Since: 02 Jan 2015
Location: pontyclun
Posts: 433
Air con needs warmth to work properly. Its the change in properties of the refrigerant that gives you cold air. If the ambient temperature is cold then more then likely the aircon will seem crap..
28th Apr 2017 7:49 pm
yaxman
Member Since: 02 Jan 2015
Location: pontyclun
Posts: 433
Really wanna hook up some guages to see if its at pressurw with vehicle not running.
28th Apr 2017 7:50 pm
JMack
Member Since: 02 Aug 2014
Location: Edinburgh
Posts: 1517
lynalldiscovery wrote:
Is the viscous cooling fan driving and shifting air?
That.
Do you notice the fan (radiator) kicking in when the pressure rises?
20Bar pressure is indicative of a 35C ambient temperature, so if the fan isn't kicking in to cool the condenser then it won't cool properly and may cut-out on high pressure switch...
242 Amps is indicative of an approx 3kw load, (Amps X Volts = Watts) I'm not sure what capacity the system is, but if you have front and rear A/C then it doesn't sound excessive. (As a guide a UK hotel room is about 2kw, so a small glazed cube with 7 people in it could well require over 3kw of capacity to cool it reasonably well)
28th Apr 2017 8:34 pm
dreynolds10
Member Since: 11 Jun 2013
Location: Berks
Posts: 166
I think I have found the problem.
Compressor is definitely Fubar'd.
Trouble is I need the car this week but clearly don't want the compressor locking up and causing the belt to fail leading to worse problems.
I am thinking of getting the systems evacuated so low pressure switch will turn off compressor and also drive for the time being with econ on, at least until I can replace the compressor.
I also wonder what caused the compressor failure in the first place. More investigation needed on that one.Disco3 project
30th Apr 2017 9:14 pm
Twintorque
Member Since: 29 Mar 2012
Location: West coast
Posts: 112
Quote:
also wonder what caused the compressor failure in the first place. More investigation needed on that one.
It's an 11 year old car that's done how many miles ? I think that's probably your answer there especially if the compressor clutch has been very active
Car ac systems get a hard time given the environment they work in. I'd not be overly upset at having to replace the compressor after 11 years. Hope you get it replaced and find no other issues, remember and replace your receiver drier at the same time.
1st May 2017 2:16 am
dreynolds10
Member Since: 11 Jun 2013
Location: Berks
Posts: 166
Yep, not a surprise really. Just a shame I didn't replace whilst the body was off as would have been a lot easier
I'll update the thread once I find time to replace it. I have the part but just need to find the time.
Disco3 project
1st May 2017 7:50 pm
Twintorque
Member Since: 29 Mar 2012
Location: West coast
Posts: 112
Remember the receiver drier !
1st May 2017 9:46 pm
dreynolds10
Member Since: 11 Jun 2013
Location: Berks
Posts: 166
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