What would be acceptable ballpark pressures for the ac on a 80 to 90 degree day? 2002 quad with 4.7. Also how many gallon fuel tank do these have?

 

26gal in most

A/C pressure's?? If there isn't cold air, then you have a problem, shouldn't matter what temp outside. Sure, it might flucuate, but you can't go off of pressure alone.

HERE


and HERE

Looks like 100psi

simple google search...

 

Let me rephrase this. What are acceptable high and low side pressures for the compressor. And I thought IO have heard they will fluctuate due to ambient temperature. Surely I know if the air isnt cold I have a problem. Trying to figure out if its compressor or duct door problem. If high and low are acceptable I can move to ducts or evaporator.

 

Actually,
Probabaly the best way to check the A/C performance, without breaking into the system, which allows for loss from design fill volume is to check the temperature drop across the coil with the unit on high fan, around 1000 rpm or slightly more, nd all the windows and/or doors open, put the hvac on dash outlets only, and recirc so you're only looking at the air in the cabin, the return is up under the passenger side behind the glove box.

Start the vehicle up, set everything like I described above, now give it 10 minutes to stabilize the refrigerant system and duct work, put a thermometer under the dash near the entry point of the recirc, wait 3 -5 minutes, get the reading, then at each of the 4 registers, average them----they should all be very close, but some of us are **** about some things, compare the temps, you should expect to see anywhere from 16 degf to 20 degf depending on how humid it is when you get these numbers,\
Really dry dys will get bigger differences

If you happen to have a dual range Fluke digital or similar, this whole thing above is much easier-----and accurate

If temps are outside those ranges, you most likely have a compromised compressor, partially blocked condenser coil, condenser fan running less than design speed, low system charge of refrigerant

 

Between 30 and 45 on the low side depending on heat load. Between 200 to 300 on the high side.

 

thanks lx man.exactly what I was looking for

 

No problem.

 

Did you watch the video I posted? The guy with the New England accent explains it all. All the info is in the video including a reference chart for ambient temperature. @4:55 in the vid

 

I confess that i didn't watch it, but I do a/c work on the side

 

yes I did. thank you