Help!!! Working on A/C right now and am confused???

[seacow]

A/C fixed now...

Got it all straightened out and everything seems to be where it should be low side 35 high 215 psi. Good to go thanks for all that chimmed in!!!!!! Road trip will be much more enjoyable. Thank You


How many cans of 134 should the system take?? I have three 12 oz cans in there right now. And its only blowing 50 degress? I do have the low pressure side hooked to the port on the dryer and high is hooked to the port on the drivers side next to battery.

The US general gauges are showing low side 46psi on the very inner circle, but if I read the very outter where it says R134A it reads 10?

The high pressure side is showing 55psi inner and 15 outter??

When I just the truck off I heard kind of hissing sound coming from the blower motor area, but quickly went away and the pressure in the system is holding steady, not leaking and valves were closed.

With the truck off the low side shows 90 psi inner and 27 outter, high side shows 100 psi innner and 30 outter? See pics below first is the truck running and second is truck off.

Please help trying to get this done before the road trip in the am!!!!

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[chris142]

The retrofit charge for my 87 is 2.75 lbs. My R12 capacity was 3.25 lbs and when you go to R134a you use 85% of the R12 charge. Assuming yours is like mine you would need 44oz.

 

[seacow]

Well I think I made a mistake recharging while adding 134 I had the low side open but I also had the high side open? I just noticed this by haveing them both open did i mess anything up you think? Going back out to check the pressures right now again.

 

[seacow]

With the high closed and low open truck running I show 45 psi low side and about 130 or so on the high side, this again is reading the very inner circle of numbers? The outter line that says 134a on it reads way different. Its about 85 here now so that means I should be looking for a high side pressure around 85 X 2.2 which is around 190 to 200 just ballparking because I dont have a calculator.

 

[seacow]

I do have the NAPA variable orfice tube Evaporaotor mount in place. Its part number 801305 hope thats the right one

 

[seacow]

And everytime I shut the truck down I get a hissing sound from the the blower box area that last for a few seconds then stops the systme is holding pressure and not leaking so I am not sure what is going on???

 

[seacow]

And everytime I shut the truck down I get a hissing sound from the the blower box area that last for a few seconds then stops the systme is holding pressure and not leaking so I am not sure what is going on???

Is tand corrected while it is making the hissing sound the low pressure side increases from 50 to almost 100 psi???
Also there is no change in blower speed or anything when I go from a/c to max a/c...shouldnt there be??
Last question, to the far back right is a solinod that has a white line to it and an arm that is connecting to something below it, I have tried all sorts of different environmental control changes and it never moves what gives??
Thanks for all the help and sorry for all the questions

 

[linkman440]

Hook your gauges up with the truck off and the gauges closed. Start the truck. Read pressures. You should be looking for about 30-40 on the low side depending on ambient temp. And 200-250 high. The hissing is just the pressures equalizing.

 

[seacow]

Did what you said and at idle low is 50 high is only 110? At 1500 rpm low is 40 and high is still 110? Is there a blockage? Temp outside is around 80

 

[boxathey]

the blower speed will not change on max cool it recirculates the inside cab air by closing off the outside air port. That is the vacum operated valve you are describing.(left side top of evaporator box under hood) if it is not working when you have the controller in max cool you probably have a vacum leak on that white line somewhere.. follow the line looking for cracks or kinks. the valve requires vacum to move the door.

 

[linkman440]

You may have a bad compressor. The vanes in them go out and allow the pressure to.bypass

 

[FORDF250HDXLT]

oh man,im getting like 28 degrees at the vents with the 134a.i do have e-fans though.but still.id say your blend door isn't closing too.
i went to like 40 lbs.it was around 75-80 degree's out.i followed the little gauge on the retrofit kit.
you should hear the blend door "THUMP" solidly shut when you switch to MAX A/C. if you don't hear that,forgetaboutit.

edit,
also the old stock insulation for the HVAC box was a joke at best when new.when old it's worthless.strip it all off,and wrap the entire box with new reflective heat shield/insulation.that's the key to getting super cold from the vents.

 

[seacow]

Thank you!!!

 

[Agnem]

That hissing sound is the presurized refridgerent shooting through the oriface tube. The sound is there all the time when the AC is on, but with the engine running you won't hear it. When you shut down, it takes a second to let the presure through as was stated. You should turn your AC off before you shut down your motor... maybe a mile or two from where you are going. After all.... when you turned it on, it took it that long to get cold. You spent fuel turning that compressor. Not wringing the last bit of "free" cool out of it before you stop, is like throwing money away.

 

[seacow]

thank you