BosAg

I do not. Factory filled on my '14

digitaltrucker

Would not idling be tougher than a 45 minute ride?

MDBoostWorks

No, Cruising down the road at 2000-2500rpm+ is making that compressor do a LOT more pumping.
I Would be curious to see the high and low side pressures during these temperature swings.

digitaltrucker

I went back and looked at the posts from testing on the donor truck, it appears the donor truck had some irratic reading with the higher number resistors.


For now, the 335K range has been stellar, but has not been on any long road trips to test.


There is a member here who is in Florida and I sent him a 360k and a 330K, he texted me today and indicated he had a solid 40 temp. He returns home from Florida next week so maybe he will have an update based on his truck.


Not sure when the donor truck is going on any long road trips, at this time.

JJM

Wish I could take pressure reading while I drive. At idle they're 25/250, windows closed, 3 max recirc.

JJM

I'm using 320k.

digitaltrucker

That low of a resistor caused freezing on the donor.

mjcutri

I wonder if the cabin ambient air temp sensor is starting to become a factor at this point. I know earlier that some guys tried messing with it, but that was before we started adjusting the evap sensor. So I'm thinking that before, the evap sensor was the driving factor, but now that we've adjusted it, the cabin temps are actually getting low enough for the cabin temp sensor to come into play. It seems like this would make sense, because the cycling usually comes back after a while (30-45 min), not right away.

Would someone be able to get a cabin temp when they see the vent temps begin to cycle again? I only have 1 thermometer.

MDBoostWorks

The ambient temp sensor inside is used to let the HVAC module know how to adjust blend doors to attain the temperature you select. From my research the only thing that controls compressor cycling is the evap temp sensor and the pressure transducer on the high side line (if pressure goes to high it shuts compressor off, if pressure is too low from a low charge then it shuts compressor off)

So now that you guys are obtaining lower evap temps, now you may be having the TXV cycling the amount of refrigerant passing through the evap core, which is causing fluctuations in cooling from the core.

I think this is your more likely culprit:
TXV
The TXV is located between the evaporator core and the TXV manifold and tube assembly at the rear of the engine compartment. The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.

RLXXI

Which is what I've been saying all along, on the one side, the txv is not replaceable without taking the dash apart and even then it's operated by a sort of capillary tube attached to the evap core.

By altering the evap sensor output we are in essence adjusting the txv if only a little bit.

It might take altering more than just that one sensor to tweak it even further. There are several that come into play and vary between manual hvac and automatic hvac, I posted a list of all sensors somewhere in this thread.

Would be nice if Ford would have left well enough alone and stuck with the fixed orifice tube they use to use.

What it all boils down to is the base programming that controls the system. If Ford would dig down beyond what R&D says, the system would perform a lot better. Since that seems an improbability the best thing we can tinker with is sensor output.