Thursday, February 21, 2013 - 05:49 pm, by: Scott Vim(1uz1jz)
Been having issues with my aircon turning off on a hot day. After trying quite a few things we think we have nailed it down to the condenser. The compressor is engaging and disengaging constantly and slowly gets worse until it barely comes in at all. After I tip cold water over it within a minute it engages and stays on until it gets hot again. I have found that the fans are on more then they should be. Even with the aircon off the elec fans stay on for quite a while. The engine fan seems to be working though it has a bit of play in it. Coolant is new and full. No leaks in coolant or aircon gas. Car never overheard. Aircon bloke said replace. What is wrong with it and is there anything.I can do? Car is a chaser with 1jz vvti.
Thursday, February 21, 2013 - 08:04 pm, by: Boris Siljanoski(Z2tt)
- Faulty Pressure Switch - Too much Refrigerant in System - Too much oil in the System - Airflow Restriction infront of Condenser. - Too much Air in the System - Condenser Internally coated with Debris.
First Get somebody to put a set of Guages and see what Pressures the A/C System is running at, and at what pressure the Switch is cutting out, see if it correlates to the Switch Specs.
Do the Elec Fans come on constantly with the A/C or at a Certain time? If at a certain time, see what pressure the high side is when the Fans engage and compare it with the Compressor Cut-out Value.
You may have 2 Separate High Pressure switches a Dual Cut and a Single Cut one........ or just One Tri-Pressure Switch.
If the switches are activating when they should, then you have a problem with cooling the refrigerant down at the condenser, either because it is coated with gunk, or air in the system.
Get the System Evacced, and Regassed perhaps with Hychill. It may also help to replace your Engine Driven fan with a Electric Fan, but shrouded and covering 100% of the Radiator, or Twin Electric fans.
Are you running your A/C on Fresh or Recycle? If on Fresh, Switch to Recycle. It may help.
How hot was the day that this began happening?
Also while the system is running, feel the temperature of the alluminium line leading to the charge port near the radiator, then feel the temperature of the small (not large) alluminium line leading toward the firewall, are they similar temperature?
Thursday, February 21, 2013 - 09:11 pm, by: Scott Vim(1uz1jz)
Got an aircon bloke who was recommended from these forums. Yep he has had the gauges in twice for half an hour and found no issue! He said he couldn't fault it. But it wasn'thot enough. Today in the morning it didn't cut out once. Had it on the gauges, told me it couldn't be a blocked tx because its working as it should and is cold. Been regassed last week. But those hot days it just stops working. Even if I'm on the freeway. He told me today the aircon fans are on for too long, the condenser is a bit hot and the engine fan shouldn't spin more then 3 times once the car is shut off (mine spins freely). My car never overheats and has new coolant. Today I discovered that tipping water over the condenser gets my aircon to work properly again for a few minutes of driving until it gets hot. Then it does the same thing. The cars revs go up then goes back down as the compressor comes on for 2 seconds then shuts off. Putting water over the condenser will allow it to work properly again but not for long. Blockge or stuffed engine fan? I had it on 27 degree days and it didn't cut out once. But today was too hot for it. Everytime the aircon guy has seen it the bonnet is open and its not above 30 degrees.
Friday, February 22, 2013 - 05:04 pm, by: Boris Siljanoski(Z2tt)
Your A/C Guy needs to Have a look at the car when it is giving a problem. Note the High Side Pressures at the time of compressor Cut-out and compare with specs on the pressure switch.
But is sounds like the condenser isn't being cooled enough which is why the A/C is cutting out on hotter days
The electric fans will stay on for as long as they require, it depends on the day, fan speed, mode etc. If the Engine fan isn't drawing in enough air, the electric fans will stay on for longer until high pressure falls to an acceptable level.
If the Engine fan is definitely faulty, replacing it will help as this is what provides airflow for the condenser. Hardwiring the Electric fans to run constantly will help too and provide cooler air out of the vents and stop pressure from climbing up high on hot days.
Friday, February 22, 2013 - 06:07 pm, by: Scott Vim(1uz1jz)
At 100km/h do you think there would be enough airflow to not even need a fan? Because it plays up even on the freeway. The intercooler blocks the condenser pretty well but heaps of people have done this. I've got a spare condenser but its a big job and needs to be regassed so I just wasted money gassing it a week ago. So hoping there is some other way. What about the condenser filter can that be changed without taking out the gas?
Friday, February 22, 2013 - 08:14 pm, by: Boris Siljanoski(Z2tt)
At 100km/h you should not have a problem, it all depends how much air is getting rammed through the Condenser and how much it would rely on the engine fan to keep the airflow going.
The Reciever/Drier to be changed, requires the gas to be taken out.
You need to rule out what is actually happening. Is the compressor cutting out when your on the Freeway, perhaps splice a LED Light into the compressor wire then run it inside your car, then see if the compressor is cutting out.
Like I said, see if the Pressure switches are working like they should, If they are then you have a problem with your condenser, if even at 100km/h the condenser is probably clogged from previous compressor failure and may need replacing, too much oil in the system hindering heat exchange, lots of things that could be happening.
Hi Scott, I've not had this issue with my Soarer, but I did with a 100 series landcruiser. The vehicle started burning out clutches as it doesn't have the safety switch on the compressor like the Soarer. Our AC guy (we live in Africa so these guys are clever but they don't have all the modern equipment) was confused. We blew through the whole system with nitrogen, but the compressor would still overheat very quickly. Another AC guy who specialises in car AC advised us to change the condenser, said he'd seen this problem several times and it was always the condenser. We took the condenser off and blew it through and it seemed fine. A new condenser from Toyota is hugely expensive and I was trying to avoid that. Finally I got an after market condenser for a much more reasonable price, fitted it, and the problem was instantly cured! So the guy advising that you change the condenser may well be right.
Monday, February 25, 2013 - 09:22 am, by: Scott Vim(1uz1jz)
Ok I've found that if I open the bonnet the aircon will work fine. Once the bonnet is closed it starts playing up. So its done sort of airflow problem. I know a lot blokes have fmic without issue though.
Tuesday, February 26, 2013 - 01:56 am, by: Boris Siljanoski(Z2tt)
maybe opening the bonnet is giving the fan easier way to draw more air in. you need to rule out all the things i said before making a decision... such as switches cutting in when they should... oil level not too high. no air in system and engine fan operating like it should to full potential..... after you have ruled all these things out then you can change the condenser and make sure to change the drier just before it gets regassed
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Tuesday, February 26, 2013 - 01:22 pm, by: Scott Vim(1uz1jz)
It was playing up yesterday so I took it to another A/C bloke. He was pretty honest actually. Without charging me he hooked up the high and low gauges. Found it had plenty of gas and wasn't cutting out due to high pressure. He checked the wires and said no signal was getting to turn the a/c on. So he is thinking electrical. He said he can took through it one day but he said he doesn't know if he'll find it but won't tell me to start changing stuff if he isn't absolutely sure. I'm determined to fix it though. Pisses me off.
Wednesday, February 27, 2013 - 02:34 am, by: Boris Siljanoski(Z2tt)
If no signal were getting to Turn the A/C on, it would never come on in the first place so that does not make sense.
Did he physically rule out that the pressure switch was not the problem? By unplugging it and bridging the wires on the plug? Or was he relying on his Guage readings to make the assumption that the pressure switches were OK?
The only other thing I can think of that might be causing the A/C to turn on when head pressures are high is perhaps the clutch coil Circuit goes Open when the compressor gets very hot.
Perhaps the Lock-up sensor could be playing up on very hot days, But that would make the A/C Light flash.
Tuesday, March 12, 2013 - 09:49 pm, by: Allan Langford(Allan)
yes you can get capillary action and oil out at the ecu end... I still think it's your high/low pressure switch that is playing up... hook up a light to the pressure switch and run the light inside the car so you can see what it's doing.
Tuesday, March 12, 2013 - 10:28 pm, by: Scott Vim(1uz1jz)
Ok aircon bloke told me that earth is being cut to the 'magnetic clutch' relay. The relay is fine. That signal comes from ecu. So I put in another one and it worked for about half hour and began to play up again. The old ecu had some sort of oil in one of the connectors. Since it started to play up with the new ecu I thought must be something else. I took out the new ecu and it had the exact same oily pin plugs. Tonight I cleaned it and it worked without stopping for my trip home (10 mins). The loom doesn't feel oily. The a/c bloke told me if he earths the relay the a/c will run all day long. What do you guys think? I noticed as well sometimes a/c revs the car to 1,300 rpm and sometimes only 900rpm. Sometimes when it shuts off it will stay off for hours. Sometimes it will work for an hour without issue. Sometimes the revs go up and down as the clutch engages and disengages within a few seconds. It's pretty random.
You need to Monitor the Output voltage from the pressure switches and see if they are cutting out at time of compressor cut-out.
1. Take the plug out of the pressure switch, find out which wires are Power supply to the switch, now use the other wires and splice into them, such as jamming a stripped wire into the slot and then plugging the pressure switch in (Careful if you do this incorrectly and short things out it won't work)... now hook the spliced wires upto a test lamp and run the A/C.... when the compressor cuts out, see if the test lights light up.
Once you have that ruled out, look into replacing the Climate Control Unit, as this signals your ECU... then your ECU Triggers the relay.
Your A/C Guy cannot tell if the switches are working correctly by gauge readings alone.
The Climate Control Unit Monitors the feedback from the pressure switches, if the high pressure switch or low pressure switch has not tripped, it will maintain Voltage or Earth (Depending on Model) to the wire to the ECU.
The ECU acts on this Signal, when the ECU receives the Signal from the Climate Control Unit, it will now trigger the A/C Magnetic Clutch Relay.
if Indeed the A/C Relay is not getting earth while the compressor is cutting out.... then either the Pressure switches are not working correctly, the Lock-up Sensor is playing up (In Which case the A/C Light will flash in most models when the problem occurs), or the Pressure Switches are playing up
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