1eye

45 pis sound way LOW for the high side pressure to be. Have to check my books tomorrow for real figures [ its been a few years since I've done A/C, I'm a little rusty ] Hang in there, i'll check and get back to you.

Bumpin' Yota

Subscribed!

Lifelongtoy

subscribed?

DudeBud

that means he wants to keep updated...



45 psi is way to low for the high side. I'm surprised thats enough pressure to turn the compressor on. you should be checking the low side psi what is that at?

ssupercoolss

ballpark high side should be in the area of 200 lbs or more.(when its on) if your high and low side show the same reading while the compressor is spinning, you have compressor failure. are any of the lines, or filter getting cold? anything dripping condensation? if so, that would tell me your a/c is working but battling your heater. i do a/c work for a bunch of knuckle heads that drive tri axel dumps. every spring they come to me and tell me their air is not working. every spring i ask them if they closed their heater valves going into the cab. 90% of the time they dont come back. so....make sure the heater valve is working properly and shutting off the coolant to the cab. hot air will be the winner in this battle. does your a/c blow cold after the truck has been sitting overnight? if so it is your heater valve.

i can only come up with 3 reasons this would be happening: 1 - heater valve. 2 - catastrophic compressor failure. 3 - improper vacuum/fill.

your next post should include high/low side readings while compressor is engaged.

1eye

At a ambient temp of say 70F your high side should be at least 100psi ranging up to almost the 190psi. Low pressure side should be running somewhere between 20psi to mid 40s psi. At around 90F it would be somewhere in the range of 150psi to 250psi. Note: the warmer the ambient temp the greater the highside pressure will be. Low side pressure is not affected nearly as much by ambient temp. It sure sound like you did not get enough refrigerant back into the system. You could try adding small amounts to it until your pressure starts to get back up into the proper range, {do not add more than 1/2lb charge at a time} What did the original system hold for a charge of refrigerant and/or what did the convertion kit to R134a tell you to put in? Is there any way to tell [even roughly] how much of a charge you put in the first time? Good luck.

Lifelongtoy

My problem now is that I can't get anymore than about 6oz into the system. With the clutch engaged and compressor running. I don't understand, it just won't go in. The can stops being cold and nothing else flows. No amount of shaking seems to work.

And after entering that half a can, the low pressure reads 60-70 psi. The high side is much higher.

BigWavePaul

iTrader: (1)

Did you do the following? Because I'm heading to AutoZone to borrow a vacuum pump. I thought I'd have to buy one for $300. Thanks for the info on the loan a tool!

Evacuate and Charging Procedure.

Attach a/c manifold gauges to the vehicle. Make sure you attach the correct hose to the proper service port. This is very important to prevent personal injury! Attach center (Yellow Hose) to a UL approved a/c vacuum pump. Open both of the dials on you?re a/c manifold gauge set. This will allow the system to be evacuated through both the low and hide side of the system. Turn your approved vacuum pump on starting the evacuation process. 30 minutes usually will be enough time. If vacuum pump has ballast read the owners manual concerning this option.

When system has achieved a state of 29.9 hg?s of vacuum close both dials on the a/c gauge set. You may loose up to 1 hg for every 1000 feet above sea level depending on the capacity and quality of pump. At this point wait 5 to 10 minutes letting the vacuum boil off any moisture trapped in the refrigerant oil. This is also a good time to watch and see if vacuum has returned to a zero state. If so you need to check for leaks in the system. Assuming the system is holding a vacuum after letting the moisture boil off repeat the evacuation procedure again. This process may need to be done a few times before all moisture has been removed and you see no degradation in vacuum after closing both dials for 5 to 10 minutes.

With both dials closed remove the center charging hose attached to the vacuum pump and connect it to either a can tap and refrigerant or 30lbs refrigerant cylinder. Open the valve on either the can tap or 30lbs cylinder allowing refrigerant into the charging hose. With refrigerant in the charging hose slowly crack this hose at the manifold gauge bleeding off any air that may have gotten trapped when moving from the vacuum pump to the refrigerant source. Only the slightest amount of refrigerant should be released in this process so be sure to tighten the charging line quickly!

Open only the low side dial on you?re a/c gauges allowing refrigerant to flow into the system. Again I stress the high side must be closed or you may cause personal injury to yourself or others! Start vehicle and turn on the a/c system with blower on the highest speed. In some cases if the compressor clutch has not engaged you may need to by pass the low pressure cut out/cycling switch. Refrigerant should be charged as a gas but in some cases it may be necessary to charge as a liquid. Be careful not to slug the compressor with liquid refrigerant! Charge system to OEM amounts and pressures if you are using the refrigerant the system was designed for. If vehicle is has been or is being converted start with about 60 percent of the original charging amount. After getting 60 percent of the original charge slowly add an ounce at a time until you reach the best possible vent temperature and pressure readings. If you do not know what your systems operating pressures are you can use the 2.2 x the ambient temperature as a guide. This should only be used as a guide as many systems will need more or less refrigerant to achieve proper cooling.

Having a weak fan clutch or an inoperative electric fan will cause system pressures to be incorrect. So make sure these components are working correctly before charging a system!

In lower ambient climates, doors and or windows of the vehicle maybe required to be open to achieve proper cooling when charging the a/c system.



this was HERE, where I bought my aftermarket A/C system

Lifelongtoy

Sure did, word for word. Exept only 6-7oz will go in.

Lifelongtoy

I even got a new cycling switch

BigWavePaul

iTrader: (1)

My system is screwed too. My high side is still 0 after evacuating the system. I had 50 psi on the low and no high pressure. Now, I have 100 low and no high pressure again. This is weird. My system wasn't evacuated after I installed it a couple of months ago. Driving my truck is unbearable here in North Alabama right now. The system had a recharge kit worth of r134 but today it was vacuumed out. After trying to charge the system another time, I think that I've reached the limit of my mechanical abilities. I have absolutely no idea what the heck I'm doing. This has been a major pain in the butt. I bought the system and had a 'friend' help me install it. He didn't know squat about the job. The dude suggested that evacuating wasn't necessary. So, after paying that guy $250 for his expertise, I have a $760 useless air conditioner that is brand new and doesn't work. Should I..

A. Take the 3rd gen to a mechanic and drain the system for a small fee and then try again to charge the system after another evacuation attempt

B. Take the truck to someone that is used to this headache and decide not to intentionally roll it to murder it once and for all and pay through the nose yet once more for cold air

C. Take off the doors, park it in the ghetto with the keys in, and pray that it isn't just stripped so that it will be a complete loss when it's stolen

Edit: I think that my drier's frozen since my high side pressure is still 0, drier ordered-much knowledge gained. The AutoZone DVD about A/C was a tremendous help along with everyone's input online. Anyone can rent that DVD, I highly recommend it.

Expansion valve and drier installed, proper amount of refrigerant added after evacuating-now 46 degree satisfaction in late August- Advice: start A/C work in November not April, ugh

trekker81

Im having problems with my retrofit, the lower the rpm on the compressor the higher the pressure is on the low side.. so if the engine is idling at 1050 rpm with ac on and I shut it off the idle goes down to 700rpm then it goes from blue to yellow on the gauge, anyone know what that means or is it normal.

mr toytech

the proper conversion from r12 to 134 is whatever the amount is for r12 put 80% of that total back with 134. and make sure you put the correct oil in it for the r134. and the correct gauge reading should be about 35 to 40 psi on the low side and 200 to 250 on the high side. the low side is the larger tubes and the high side is the smaller tubes.