What pressure should I be reading at my low side port?

Ford Expy 97

 

At idle with the compressor on, about 30-32 psi on the suction side is good, although it can go up to 40ish. The low side should go down as engine speed increases.

 

I get a reading of 45psi with engine on and start to go down very slow to
43 psi when I turn on the back console on my Expy.
Do I have to much 134a in my system? what should I do if so?

Marcos

 

I get a reading of 45psi with engine on and start to go down very slow to
43 psi when I turn on the back console on my Expy.
Do I have to much 134a in my system? what should I do if so?

Marcos

 

If it's overcharged, the system needs to be drained, swept and recharged. 45 psi is a bit high at idle, how is it cooling? High low side pressures at idle may also mean that there's some moisture in the system.

 

Well, with front console takes a while but if I turn on back console
temperature getspretty cool.

one thing; when last time I recharged the system,I turned on the 3 consoles.

Did I do it the right way?

Marcos

 

Running down the road or with a fan in front of the engine it runs okay? I don't suppose you got a thermometer you can stick in one of the vents to monitor temperatures, do you?

You did pull a vacuum on the system before you recharged it, right?

 

I just bought a thermometer today,so I will monitor temperature
when driving. Let you you
Yes I did pull a vacuum on the system before I recharged it.

Marcos

 

Just with front console blowing, I get a reading of 19 degrees celsius.
If I turn on the back console,then it drops to 14 degrees celsius.
outside temperature od 30 degrees.


Marcos

 

Low side =45psi while high side rises just rises to 200psi:
do I have a bad compressor?

Marcos

 

19 degrees C is about 66 degrees F...and that absolutely sucks at the vent. I'd be tempted to say either the system's undercharged or it's got some moisture in it.

Are your pressures staying steady at the guages or doing anything weird like flucuating rapidly or the like?

 

The high side pressure is good at 200. The low side being high could be moisture in the system like Quintin said. Did you pull a deep vaccuum on the system before charging it. I have had several vehicles with similar problems come in. Usually it's on systems that have been charged recently. Either the system was not evacuated long enough, or the accumulator is saturated with moisture causing it to freeze up and cause flow problems. I usually pull a vaccuum for about 1 hour. Just to make sure all of the moisture is out of the system. How are the temps of the lines? Check the temp just before the orifice tube, after the orifice tube, and the line going into the accumulator from the front evaporator. Also check the temp of the lines at the back for the rear unit under the vehicle.
Does the A/C behave the same whether you are sitting still or moving down the road?

 

thanks guys for getting back to me.

I did pull a vaccuum for about one hour before recharging the system
again, and I suposse I got not moisture since the low side is
not fluctuating at all. Low side is high cause I recharged the system
until I had 45psi thinking that it would solve my problem. With 40psi,
I was getting 160 in the high side which was not good.
Yes temperature gets better when moving down the road

One thing I notice, is a snorgle noise coming from the compressor which was not
there before.

thank for your help guys

I'll check the lines

 

Sounds like you overcharged the system. 160 on the high side is ok at idle. It's a little low, but not too low. If you do not have the proper tools to measure the amount of freon you are putting in, then I would recommend taking to a shop just for the evac and recharge. R134 is fairly cheap. It should not cost you more than about $75 to get it recharged. Then if you are still having problems, we can go from there, but it is really hard to try to diag it when it is overcharged.

 

Thanks SVT,

I have new gauge and I keep getting 45psi low side and 200 high side.

What happens when the system is overcharged?

This weekend I will evacuated the system maybe there is humidity somewhere.