A/C question

[Stresst]

Most of you already know my a/c is still giving me issues and im trying desperately to figure it out.

So my question is what is the low side pressure supposed to be? I read somewhere that you are supposed to set the a/c up so it blows cold on a hot day. So set it up for a 100 degree day which means low side pressure of 70lbs (supposed to be 30lbs under the ambient temp). Ok, sounds good to me (someone who doesnt know anything bout pressures).

But then I read somewhere that you do not want no more then 47lbs or you will not blow cold at idle.

So what is the pressure supposed to be on the low side at idle? @ 2000rpm?

 

[SunlitComet]

Try an see if you can match your reading to this. It is for the 1999's :

1. Park the vehicle indoors or in a shaded area.
2. Open the hood, the doors, and the windows in order to ventilate the interior.
3. Vent the engine exhaust, if necessary.
4. Install the high and low side pressure gauges.
5. Route the lines over the front of the grille.
6. Close the hood completely.
7. Record the ambient temperature near the vehicle.
8. Record the temperature and the relative humidity by using a psychrometer or by consulting the local weather bureau.
9. Close the doors.
10. Close all of the windows except for the front side windows.
11. Set the mode control to the A/C position.
12. Set the blower control on the HIGH position.
13. Set the temperature control to the FULL COLD position.
14. Open the air conditioning outlets.
15. Install the J 21213-A into the right center air conditioning outlet.
16. Place the transmission in park.
17. Start the engine.
18. Stabilize the engine speed at 1500 RPM .
19. Start the timer.
20. Operate the air conditioning system for 10 minutes .
21. Record the following data:

• • The outlet air temperature
  • The high-side pressure
  • The low-side pressure

1. Turn the ignition to the OFF position.
2. Compare the readings to the table below.
3. If you suspect a malfunction in the refrigerant system due to abnormal system pressures, inspect the system for the following conditions:

24.1. The outer surfaces of the radiator and the condenser cores are blocked by dirt, leaves, or other material. 24.2. The areas between the condenser and radiator are clogged with dirt, leaves and other material. 24.3. The evaporator core, the condenser core, the hoses, the tubes and other components are restricted or kinked. 24.4. The system is leaking refrigerant. 24.5. The air ducts have leaks or restrictions. 24.6. The airflow rate is low due to a restriction in the evaporator core. 24.7. The compressor clutch slips. 24.8. The drive belt tension is improper. 24.9. The accumulator is plugged. 24.10. The expansion (orifice) tube is plugged.

 

[Stresst]

Can you send the chart to [email protected] so I can print it. I cannot see it......

 

[SunlitComet]

Done.

 

[Stresst]

Thanks, so according to that chart there shouldnt be more then 47lbs on the low side @ 1500 rpm so rite off the bat me with 50 at idle is a problem!

 

[SunlitComet]

I can't say what was the Outside air ambient temperature and humidity level when you did the test? And what did you have for the high reading?

 

[Stresst]

Can someone tell me measurements of there condensor. Wanna compare to my aftermarket unit. While installing the fan noticed it looks real small, but not sure....

 

[Stresst]

I just got back from installing my electric fan, didnt make the temp inside drop 1 degree.

Outside temp is 79, low pressure is 35lbs at 1500rpm while the high is about 235. Both needles were steady, no bouncing like I seen on some cars in the past. Inside car temperatur was 60, humididty is 59%.

Another thing is I just cleaned the evaporator, last week my buddy removed the motor and all I seen was a few leaves other then that it looked almost new. But I was wrong, it took me over 2 hours to clean it out. All around the edges out of sight was leaves, oil and grime. Used about can half coil cleaner from home depot. More I cleaned more crap came out. Finally everything came out clean.

THE ONLY EFFEENNN PROBLEM IS THE A/C IS THE SAME WAY! WHAT AM I GOING TO DO????

 

[SunlitComet]

Just throwing this out there but how about change the charge actively for finding the biggest inside temperature split between inlet and output ducts. That is about as good as it can get unofficially. But you will have to judge the pressure gauge for you self to make sure your don't stress out the pump with high pressure. And we know how easy it is for your suv to get stressed.

I did the temp split method on a few hundred apartment units all the time for A/c unit because they kept on blowing there tops the efficiency and power usage was much better afterwards. Being as how auto's have cycling compressors it will have to be done by averaging multiple readings over a specified time and changing the charge a few ounces at a time up or down and zero in on what works best without stressing out the system. This will get time consuming. Also do you have heavily tinted glass that may help keep the light out of the interior?