Air con problem.Bit confused
Discussion
BLUETHUNDER said:
Ive had it two years.And to be honest ive never had it done.
Maybe worth a shot, it should be done every 24 months or so as the gas natually disapates. I know some systems have a pressure switch that senses the pressure of the gas and will not cut in if the pressure is too low, I guess you could also check this switch too!
In theory you should never need to re-gas it.
The gas isn't consumed, hust circulated.
In reality they do leak a tiny amount over a period of time, and often when they are left off for long periods.
If the gas left in the system is borderline to the point where it will be able to switch on the pressure switch, then you may find sometimes it cuts in and more times it doesn't.
This will be due to the gas pressure being directly affected by heat (warm engine / warm day, etc).
But if it is this borderline then it will cut off immediately again once the compressor starts and "sucks" gas from the pressure switch.
Have it checked out.
Any "fridge man" should be able to do it for you once they have the adaptor fitting for the compressor.
The gas isn't consumed, hust circulated.
In reality they do leak a tiny amount over a period of time, and often when they are left off for long periods.
If the gas left in the system is borderline to the point where it will be able to switch on the pressure switch, then you may find sometimes it cuts in and more times it doesn't.
This will be due to the gas pressure being directly affected by heat (warm engine / warm day, etc).
But if it is this borderline then it will cut off immediately again once the compressor starts and "sucks" gas from the pressure switch.
Have it checked out.
Any "fridge man" should be able to do it for you once they have the adaptor fitting for the compressor.
I was investigating aircon last year. With a bit of advice from Jools at TCS I sorted out how the AC clutch gets energised.
Details are in my post on this thread
Details are in my post on this thread
BLUETHUNDER said:
So what your saying is that the reason that i some times get the aircon to work,is due to the amount of refregerent in the system at the time passing the switch?
The amount and type of refrigerant is crucial.
I Sold mine last year, and so had it regassed 1 week prior to selling it, when Dave came round to test drive the car, the Air con wasnt working! He bought the car, and took it to a different A/C place and got it regassed, since then the Air Con has worked perfectly for him, no other changes were made.
I think the place I went to put in 1kg of gas, the place Dave went to put in .75kg. So if everything else is working, the amount of gas can make the difference between the A/C working and not working.
Dave - Correct me if I'm wrong on any of this
BLUETHUNDER said:
When i some times press the aircon button it doesnt work.Other times it does.I know the button is working because i can hear a click coming from down near the E.C.U.Its just that at times the clutch either ingages or doesnt.Any ideas.
Mark.
Mark.
The griff a/c is a very simple set up,and i would expect the Cerbies to be the same.An output 12v is sent to the pressure switch on the receiver drier the instant you turn on the a/c(this output comes from the heater ecu on a griff).If the switch 'says' the pressure is good,the the 12v goes back to energise the compressor relay,allowing the compressor to run.This is 'basically' how it works.
It sounds like the click you can hear is the compressor relay being energised.If this happens every time you turn on the a/c,then the fault will be from the output of this relay,to the compressor,or indeed the compressor itself.I'd check the relay and its housing/connections first,then the connection at the compressor,where it joins the loom.
The Cerbera Air Con is further complicated since the A/C switch-pressure switch-rheostat just put a voltage onto one of the ECU pins.
The ECU then 'decides' if its going to permit the A/C to work and if it does it pulls another pin to 0V to turn on a second relay.
It uses the intercooler spray feature of the MBE to do the deciding. This enables teh ECU to deny a request for the A/C to be turned on if certain conditions are not met - air temp, coolant temp, rpm, throttle site etc.
Specifically its said that the A/C is not enabled over certain rmp and/or throttle sites. But the settings Trackcar and I have seen in the ECU don't seem to support this.
Has anyone any experience of the A/C being turned off at high revs and wide open throttle?
I can't remeber if Joo and I tried it with my car on the rollers. But I don't think he has ever seen any evidence that the A/C does get turned off.
The ECU then 'decides' if its going to permit the A/C to work and if it does it pulls another pin to 0V to turn on a second relay.
It uses the intercooler spray feature of the MBE to do the deciding. This enables teh ECU to deny a request for the A/C to be turned on if certain conditions are not met - air temp, coolant temp, rpm, throttle site etc.
Specifically its said that the A/C is not enabled over certain rmp and/or throttle sites. But the settings Trackcar and I have seen in the ECU don't seem to support this.
Has anyone any experience of the A/C being turned off at high revs and wide open throttle?
I can't remeber if Joo and I tried it with my car on the rollers. But I don't think he has ever seen any evidence that the A/C does get turned off.
The AJP Griff said:
BLUETHUNDER said:
When i some times press the aircon button it doesnt work.Other times it does.I know the button is working because i can hear a click coming from down near the E.C.U.Its just that at times the clutch either ingages or doesnt.Any ideas.
Mark.
Mark.
The griff a/c is a very simple set up,and i would expect the Cerbies to be the same.An output 12v is sent to the pressure switch on the receiver drier the instant you turn on the a/c(this output comes from the heater ecu on a griff).If the switch 'says' the pressure is good,the the 12v goes back to energise the compressor relay,allowing the compressor to run.This is 'basically' how it works.
It sounds like the click you can hear is the compressor relay being energised.If this happens every time you turn on the a/c,then the fault will be from the output of this relay,to the compressor,or indeed the compressor itself.I'd check the relay and its housing/connections first,then the connection at the compressor,where it joins the loom.
I spent a couple of weekends chasing all the electrics to find out what was causing the problem. Turned out it just needed regassing so it was the pressure switch that wasn't engaging.
That switch is in the wing in front of the near side wheel and gets sprayed via the hole under the front indicator. So it may simply be bad connections.
You can test the pressure switch is closed by checking for a voltage. Have a read of the thread I linked to in my post above. It describes a fault finding procedure to determine whats not closing.
If you don't feel up to wielding a test meter then I would get the gas checked by an A/C place before you hand it over to an Indie or a dealer for fixing.
That switch is in the wing in front of the near side wheel and gets sprayed via the hole under the front indicator. So it may simply be bad connections.
You can test the pressure switch is closed by checking for a voltage. Have a read of the thread I linked to in my post above. It describes a fault finding procedure to determine whats not closing.
If you don't feel up to wielding a test meter then I would get the gas checked by an A/C place before you hand it over to an Indie or a dealer for fixing.
Edited by mikesr on Saturday 31st March 14:05
My aircon has never worked. When changing the radiator this week I did notice that the aircon pipes rub against the chasis in one or two places and in one place in particular it has cut throught the pipe. I had to remove the F1 pannel and the offside air box to have a really good look. I intend to repair the pipe and re-gas soon...ready for le-mans!
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