[tperk100]

Starting from an evacuated system, I tried to weigh and install my refrigerant. Turns out my refrigerant hose on my gauge set had a leak so only a portion of my 134a actually went into the system. When I was finished and realized that the system was not cooling, I put the gauge set back on and this time was paying attention to the pressure readings. In 100 degrees, AT IDLE, the reading were well below the acceptable range on the chart.

So there I was right back to guessing how much refrigerant the system needed. I started adding refrigerant, AT IDLE SPEED. After adding about 20 oz, I was getting readings in the middle to the high part of the recommended range....seemed real good and now the system was cooling well.

HOWEVER, when I increase rpm to about 1200, the pressure readings go OFF THE CHART!...way high! So I am trying to decide if I have over charged the system. The FORD factory manual says to charge the system at IDLE speed, which is what I did and got good readings at this speed.

Is it normal for pressures to go REAL high at faster than idle speeds. The system is cooling REALLY WELL with over a 40 degree temp drop across evaporator. Am I over charged?

Any comment/help will be appreciated.

 

[jims327]

Usually at a higher RPM, the pressure will drop alittle not increase, Ford says to add the freon at idle, however, I had an issue that after awhile at driving at 70mph, it would blow warm air, come to find out, my pressure was dropping too low, so I added my freon at 1500 RPM, no problem with it, not sure what gauge your using to read, hope it's not the one that comes with the bottle, (you know, the blue hose with the guage on it), I've had issues with them before, toss it and get a good one

 

[tperk100]

Everybody eats crow once in a while....I guess it's my turn. Put gauges (REAL ONES) back on this morning, paying more attention than before.

Ambient temp 95

Static engine off 105/105
Static engine idling 105/105

Engine Idle AC & Fan on MAX 45/265
1200 RPM 35/325

Short Road test...
Ambient 95
AC Vent 45 !!!

I have NO IDEA of where I came up with "OFF THE CHART." The system seems to be working GREAT, cooling better than I can ever remember.

Thanks much

 

[chuckster57]

Everybody eats crow once in a while....

Tastes pretty good if it's cooked right:thup:

Well at least you used the right equipment to service your A/C system. I have had to fix a lot of peoples A/C after they think they needed to hook up that little can with the dial on the top and then wonder why their A/C won't blow cold..."must need more" is the usual complaint. Manifold gauge sets are a key part of diagnosis.