88-94 5.7 Suburban A/C Diagnosis and Tuning

[cjcb1100]

my accumulator is always wet from condensation so is the back and body of pump

 

[L31MaxExpress]

well when i had 3 24oz cans in it my low side was super low like 14 psi

I do not know how it could be at 14 psi with a properly functioning cycling switch. The switch cuts out the compressor around 20 psi.

If the compressor is not cycling, the evaporator core will quickly build up a layer of ice that blocks heat transfer thus warmer air and eventually no air.

 

[cjcb1100]

yeah it was cycling off and on new 134a switch

 

[cjcb1100]

the goal is to have it cycling at idle? was always told that was a sign of it being low on charge?

 

[cjcb1100]

wish i had the money to just drive down to you for some help i live just north of okc

 

[cjcb1100]

You must be registered for see images attach

This is in my wifes car its 95 outside and it gets cold not as cold as it use to but far better than the k2500 my pressures in the k2500 are similar

 

[L31MaxExpress]

the goal is to have it cycling at idle? was always told that was a sign of it being low on charge?

I have had them cycle at idle, the system cycles as needed to prevent ice accumulation on the evaporator core. Under 90°F it would not surprise me at all if it cycles a bit even at idle.

 

[L31MaxExpress]

You must be registered for see images attach

This is in my wifes car its 95 outside and it gets cold not as cold as it use to but far better than the k2500 my pressures in the k2500 are similar

With 4 pusher fans on the condenser, I would think you have a bit more airflow. The more airflow the lower the pressures will show. Have you disabled the pushers to see where the pressures sit?

 

[cjcb1100]

No i jave not just 2 pushers and mechanical pulling

 

[pressureangle]

A couple things, hopefully to clarify;
1. Low side pressure loosely correlates to evaporator temperature. If you have 14psi on the low but poor cooling, the evap has iced up and can't flow and cool much air.
2. Refrigerant is condensable; what that translates to in the real world is that you will not see any change in pressures until you actually hydraulic lock the high side; short of that, the condensed liquid simply fills up more of your condenser- which means you have less functional condenser available and when it's working hard may fail.
So. Get your system hot and stable at idle, then with your hand or if you have one a temperature IR gun feel your condenser and find the height at which the temperature changes. Where there is gas, it will be hot. Where the liquid has condensed, it will be noticeably cooler. Best performance is actually where there is a minimal amount of condensed liquid in the condenser, usually quite a bit less than the recommended volume of refrigerant. If you find the temperature change around 1/4 to 1/3 from the condenser bottom, you're in the recommended range.
I recently replaced my entire A/C system in my '94, every single piece- I added the oil into the accumulator and compressor as you have, and discovered that the oil took a lot longer than I expected it to to mix and pass into the system and stabilize. Early on, I had poor performance and high compressor load. It was probably a half-hour of run time before it was working normally. Too much oil in the evaporator entry can restrict flow, which results in low suction side pressure.