High Rpm/ Air Con issues

[Dad Racer]

Some advice is greatly needed. Last month, my 850 T5 developed an interesting fault.

The aircon started to blow 'unconditioned air' + at idle, the rpm started to sit anywhere between 950-1800. Turned aircon off - problem remained. Turned off climate control - rpm returned to normal. Turn off/on ingnition - aircon works fine + rpm normal. After a couple of minutes, compressor cuts out, warm unconditioned Air + high revs.

Had the aircon recharged, seals checked etc - fault still remains. Had the idle control valve cleaned - problem remains. Have trawled this forum, but nothing found that fits.

With the climate control turned off - rpm stabilises around the 1000 mark and sounds a little ropey. Have had the lamda light on for while and had it read - idle fuel trim?? Not sure if this is related.

I am convinced that there is a problem with the aircon somehow. Always when the compressor kicks in. Anyway, I am at a loss and so is my local garage.

[jim.kelly]

hi mate, reckon you and me have the same prob, mine does exactly the same, my mechanic is scratching his head on this one, he reckons he mite have to take the front wing off to check the wiring, he had it for a week, sometimes the ac worked then it sdidnt, when the ac was running he took it for a spin, gave it some welly and the ac stopped bloowing cold.
lets hope one of the pukka mechanics on this site can help out.
still it not that hot now, lets hope its stays like this till we get em fixed
jim.k

[adriancole]

My aircon used to work for a less than a min then cut out, turn engine off then on again same thing happened...

What was found to be happening was there was a resistance in the high pressure side of the condensor....unfortunatly a new condensor was needed...not that cheap though recon parts available........i had taken car to several "specialists" to no avail till i found Stu at SW Autos in Biddenden Kent, who worked it out in literally ten minutes.......fixed in less than half hour....was very happy as it was just before the heatwave...

[TwistedSanity]

i would test your car battery/alternator, mine had all sorts of problems caused by a weak battery, the car started every time though, definately worth a try

[Dad Racer]

Thanks for the replies fellas. Will think about that one - how do you test for resistance in the high pressure side of the condensor?

I have had problems with the temp guage/ sensor. Sometimes the temp needle would drop to zero. Read somewhere that this might be connected. It seems to make sense as it almost feels as if the engine is compensating somehow - there is a draw on the engine. Haven't had a good look to see if the engine idle rises when the fan kicks in. Confused???

As for turning the aircon off, the same problem still occurs. I think that the tripping off of the aircon is a side effect, which leads me to think it might be an electrical fault elsewhere.....There is something drawing power from the engine which is causing the idle to run high and i think that the aircon is getting shut off as part of the cars LOGIC circuits - i.e dump un-nessessary systems.

[Dad Racer]

Just found this - very interesting to this problem:

http://www.vpcuk.org/forums/t3301-air-conditioning-discoveries.html