Hello Exmen!

I replaced my compressor and drier and filled the system with 14 oz of PAG Oil. I filled the system with refrigerant and the low side gage sits at about 60psi with high side gage at 60psi. The compressor keeps cycling every 3-4 seconds and wont stay on. I think I still have a small leak. Why is the compressor cycling so rapidly and wont stay on? What would be my next steps?

 

Do you have a front and rear system?
Did your new compressor come dry, with no oil?
Did you drain and measure the oil from your old compressor to determine that you needed 14oz?
Did you evacuate the system with a vacuum pump to 32 hg, or 800 or less microns?
How many pounds of Freon did you charge the system with?

Sorry for all the pointed questions, but all of them are pretty important, and the answers would paint a better picture on how you arrived where you are at...

 

 

That would be completely normal up to that point as you're were charging into a vacuum, but it would be my opinion that you were not sufficiently patient.

Once the clutch starts short-cycling, it's pulling in a bit of refrigerant with each cycle. With sufficient patience, you would have noticed that the ON-portion of each cycle starts to get longer as the amount of refrigerant in the system increases.

Two common shortcuts include 1) warming the refrigerant (hot water bath or set it in the sunshine for a while) and 2) jumpering the low-pressure cycling switch to force the clutch into 100% duty cycle.

 

 

+1, that's exactly where I was headed next to advise.

 

How many ounces did you get from the compressor once drained?
It's a bit of a pain, but unless you did a full system flush/clean with a flushing product, and not Freon, and started with a dry compressor, then you would *** the factory spec 14oz. Otherwise without knowing how much drained from the compressor, and accumulator, you're not going to know how much over you are. A little bit over and you won't notice much, alot and you'll have performance issues. Since you're sealed, and at above atmospheric pressure, continue as above and go from there.

 

If your high side is only going to 60 PSI, your high pressure switch is not going to allow the compressor to cycle. By the numbers being equal, 60 and 60 it would appear that perhaps that:

1. you do not have enough freon in the system. It takes about 70-72 ounces to fill it with rear air. 6.5 12 oz cans. The pressure switch will not let it run longer.
2. Your new compressor is faulty.
3. One of your pressure switches are bad or the connection is faulty on one of them

On the ex, they have two pressure switches. Both are on the passenger side of the engine. One in the compressor line and one on the accumulator.

As it is short cycling like you describe, I would look for a full charge first, then at the pressure switches. You can jump each one with a paperclip to see which might be bad. Once you get the compressor to cycle then you can see if the pressures come up.

 

Just to be certain there isn't a mistake in procedure, the high side valve on the manifold was closed while charging yes?
This would cause equal pressure on both high and low side. Ive seen it happen before when the high side valve wasn't closed after pulling vacuum.

 

I agree with the others, but did you also replace the orifice tube?

 

That will cause problems for sure. Every Ford I have owned has needed this replaced. It's on the low side though before the evap, he is not getting high pressure.

 

If both the low and the high side readings are the same and are also at the static pressure for the ambient temperature (see a P-T chart!), it simply means that the compressor ain't running, nothing else. If the manifold's valves were left open, you'd usually see the compressor operating but the pressures on the two gauges would usually be different but the difference would be markedly attenuated (it depends on how far they're open plus a other variables like temperature). Also, the high-pressure bleeding bac into the low side would tend to keep the low pressure switch closed and the compressor clutch wouldn't be short-cycling.

Just to clarify, the high pressure switch is a normally closed switch that is designed to open up if the pressure hits the upper limit, usually in the 400-500 psi range. The high pressure switch will not disable compressor operation under low pressure conditions (unless defective), it's the job of the low pressure cycling switch to take care of that low end.

He doesn't have the necessary equipment to do a full refrigerant charge except by allowing the compressor to do the last 3/4 of the work. It takes highly specialized equipment (and expertise) to do a full charge on a system that is not yet functional. The factory, for example, does have that capability to charge the system without it being in operation.

It's actually in the liquid line between the condenser and the input to the evaporator, usually right at the input to the evaporator. He's not seeing the gauges show a pressure differential because (1) the clutch isn't cycling ON long enough and 2) there's not much charge in the system yet.

 

There was less than an ounce in the compressor. I poured 8 ounces in the compressor and 6 ounces into the drier.

 

Yes i did replace the orifice tube. It had a little debris about the size of half a pencil eraser.

 

i had the high side valve closed until the compressor kept cycling then I opened it to see what affect it would have. The high side pressure dropped.

I have taken out the evap and ordered a new one today. I will also flush what i can today and reinstall the new evap tomorrow when it arrives and follow the charging tips I have received on here.