Low side normal /high side low stumped

[bohica2xo]

A full load test is all doors open and cabin fans on highest speed. Engine rpm at 1500+ and hold for 90 seconds to stabilize. Read the pressures while the rpm is still above 1500.

Easiest to simply lay the gauge set on the windshield where you can see it so you can manipulate the throttle and check the vent temps at the same time. Drop a wiper arm over the hoses or use a little duct tape to hold them where you can see them.

Idle testing is not effective for many problems. This test simulates drive away from a parking lot after a long heat soak.

[bohica2xo]

60f discharge air at idle in a huge vehicle like an Excursion or Suburban is normal at 100f A large volume of 60f air will do a lot of cooling.

Again, idle testing. What will it do at 1500 rpm? You are close with the numbers you have.

[Tim]

60f discharge air at idle in a huge vehicle like an Excursion or Suburban is normal at 100f A large volume of 60f air will do a lot of cooling.

Again, idle testing. What will it do at 1500 rpm? You are close with the numbers you have.

I was thinking the same thing; it's close. 40-degree difference from ambient is not all that bad on a large-capacity vehicle.

[bohica2xo]

Most people not located in the US have never even seen an Excursion. The cargo volume in that beast is 146 cubic feet. A rolling garage.

Just a lot to cool. And neither Ford nor GM were willing to step off the cliff and do a dedicated compressor / condenser package for those beasts with 60% more capacity. Blame CAFE for some of that too.

[tbirdtbird]

YIKES!
If I have seen one I don't recall. I just googled it.
"The Ford Excursion is a heavy duty (Class 2), full-sized SUV that was produced by Ford. The longest and heaviest SUV ever to enter mass production, the Excursion was marketed as a direct competitor of the 2500-series (¾-ton) Chevrolet Suburban/GMC Yukon XL"

I have no idea how you would cool that.
On another note, for the OP, if you are in a modern car and pull up to a traffic light, you will notice the AC doesn't perform as well as when underway.
A compressor cannot do very much work below 1500 or so RPM, that is why we always test at that RPM and not idle

[tbirdtbird]

"Ok so I did the test . So my low side dropped when the rpm was set at 1500 and I blocked off the condenser with a trash bag when I did this both low side and high side very quickly reached 330 psi for high side "

1) This test was just to determine if the compressor could still pump, and it obviously can.
Now with the plastic bag removed from the condenser, run the engine at 1500 and record pressures and vent temps
2)Long threads like this get very confusing as to what has been done and what has happened.
3)Whenever you post, stating that the low dropped some or that the hi went up a little is not helpful
You need to post your exact hi and low for every step you take, and always include vent temps. That is the only way we can help you. You use pressures not to determine charge, but to trouble shoot once the correct charge is in
4) I have re-read this thread several times and it is confusing as hell.
However I agree with the other experts here (you have no idea just how good these guys are, they are true pros and not shade tree) that you are guessing at the charge, you need to recover, evacuate, and recharge to factory 134 capacity, else you are just chasing your tail.
5) once the beast gets to 1500 RPM you must wait a while (I would say at least 5 min maybe 10) for the system to equilibrate especially since that thing is larger than Madison Square Garden. If you take readings immediately upon getting to 1500 RPM then all bets are off
6) wonder if the roof is insulated....somehow I doubt it, that would have added another dollar to the window sticker. So many cubic feet and soooo much surface area. Forget using it as basic transportation, turn off the AC and convert to a rolling pizza parlor, vehicle already has a built-in oven

[Excursion2001]

So i removed Freon and vacuumed down the system for roughly 40 mins and held vacuum . I recharged the system as close as possible to 68oz . I did the 1500 rpm test for 5 mins temperature outside was 114 degrees the vent temp was 80 degrees . the low side was 61psi and the high side was at 340 psi during the test . My truck quickly reached operational temp cause it’s so freaking hot out here but yes it is a big truck I like it a lot but I’m am taking into consideration that it is alot of of space to cool and a lot of windows but is there any remedy’s to help keep the cab cool I know the doors stay warm ? I know the roof isn’t insulated I’m not sure about the floor it just doesn’t feel like it cools down even when driving down the road for 40mins it just feels muggy . And again I’m sorry for the confusion about how I been posting I’m just stressed out about this whole situation I have a new born and I want my wife and baby to stay cool and not burn up out here . Again I really appreciate the input and energy you guys are helping a lot !

[Tim]

No one is trying to mock your attempts to find the solution. However, you do have to be realistic about what the system can handle. Therefore, you posted some relevant information in this last post.

114, sounds like Phx temps.

No roof insulation that's going to kill performance in this type of heat. The heat radiated off that roof is killing performance. Are the windows even tilted? Not that it is going to help much with little to no insulation.

Have you checked the fan clutch? Is it locking up? But with as much heat is in the vehicle. Those readings are not out of line. The system can remove only so many BTUs.

Honestly, wife and baby. No matter how much you like the vehicle. It might not be the best choice for comfort in 114-degree temps. I am just honest with you.

[Excursion2001]

No one is trying to mock your attempts to find the solution. However, you do have to be realistic about what the system can handle. Therefore, you posted some relevant information in this last post.

114, sounds like Phx temps.

No roof insulation that's going to kill performance in this type of heat. The heat radiated off that roof is killing performance. Are the windows even tilted? Not that it is going to help much with little to no insulation.

Have you checked the fan clutch? Is it locking up? But with as much heat is in the vehicle. Those readings are not out of line. The system can remove only so many BTUs.

Honestly, wife and baby. No matter how much you like the vehicle. It might not be the best choice for comfort in 114-degree temps. I am just honest with you.

I live out in 29 palms California and it can reach a lot higher than that in late July but the windows have factory tint I’m sure it’s 32 percent , Fan clutch is locking up and moving air . I did some digging and pulled some trim off and found that there isn’t any insulation . Not on the doors , side of the walls of the truck and the roof I know doesn’t have any . What would be a good insulation for this application ? And would a add on electric fan on the condenser help ?

[bohica2xo]

Wow. 5 full minutes at max load. That is hitting it hard. Good news is a pressure ratio below 3:1 even with that beat down. I am going to say the fan clutch is hanging in there as well.

I am going to say your refrigeration loop is in pretty good shape, based on pressures. A "muggy" feel, and vent temps in the 80's would indicate some reheating to me. Perhaps a blend door issue. Given that an aftermarket company like Dorman makes blend doors for the 2000 Excursion might be a reason to look there...

Also check the evaporator drain. If water is not leaving the evaporator case it can feel muggy when the car is that hot.

FYI that 5 minute run you did is like pulling the 23 foot daycruiser up the hill out of Willow Beach.

Insulating the roof could be done. It would require removing the headliner and carefully prepping the truck to spray the underside of the roof. If that is something within your mechanical abilities. I can't think of anybody doing that job commercially.