How cold A/C?

[Lablanca2019]

That is actually normal. Air conditioning does not make cold air. It removes heat from air. The slower the air moves across the evaporator the more heat can be removed from it. There is your A/C 101 tip of the day. I had actually thought about posting that earlier in the thread, but never got around to it. As your testing shows that is how it works. My truck stays coolest with ac on recirc and the blower on 4-5 i never use max as it doesn't cool as well. And it was 106 here today.

I was also gonna mention I recently converted from 1234yf to r134a, done by professional Ill also be adding ceramic film to windshield with mechanical fan it looks like we will get what we get when it comes to cold air at idle

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[airline tech]

R134a - should actually give you about 5 deg colder air than the OE. (On paper) But the truck is programmed to work via the pressure sensor readings for R1234YF - I would say this is the reason for this level of performance at idle, I would have to dig some , but I do not believe the as built files give you an option of Freon type.

 

[Lablanca2019]

R134a - should actually give you about 5 deg colder air than the OE. (On paper) But the truck is programmed to work via the pressure sensor readings for R1234YF - I would say this is the reason for this level of performance at idle, I would have to dig some , but I do not believe the as built files give you an option of Freon type.

while checking temps recently on a 76 degree morning at medium speed (4 dot) fan speed it was blowing 48 deg, So it leads me to believe that for my situation its just too damn hot here in my location, For example yesterday we had a 105 heat index,

 

[airline tech]

More of a curiosity question, a professional shop conversion- cannot be legally performed- -EPA , I feel that this conversion actually is worse than keeping the 1234 , as far as idle air performance, now at highway speeds may provide some extra cooling efficiency- my reasoning is the difference in properties of the 2 gases and the installed components that are designed to work with 1234.
The condenser- and heat removal effencieny - the truck’s OE may struggle with 134
The expansion valve is designed for 1234
So with 134 it will be improperly metered for gas flow into the evaporator.
The AC - High Pressure switch- due to the pressure properties of the 2 gases the 134 will read at a higher pressures and the PCM will react accordingly as it’s programmed for 1234, thus also affecting the cooling fan speed when AC is running.
So for me it’s a question of Why would a professional perform this or recommend this conversion- when the performance hit is worse.

I may be over thinking it and may be missing something but my basic knowledge of the system- has me wondering is the conversion worth the penalty hit in performance

 

[airline tech]

The true test to see what is going on - is to either hook up a gage set or pull up the AC Pressure PID and record the pressure at idle and driving.

From the 1234 Chart @ 100-105 Deg and 15-40% Humidity - the pressure should fall in the range of 260-274 PSI @ idle and a slight pressure drop of that reading when driving (est 20-50 psi) if i recall correctly
another important PID is the Evap Temp - should be about 35 deg - with Max AC
and then the clutch engagement PID or Compressor PID - tells us if the clutch is disengaging
AC Clutch Engaged- True or False (PID)

These 3 PIDs alone can help see what is happening.

 

[Blue Streak]

More of a curiosity question, a professional shop conversion- cannot be legally performed- -EPA , I feel that this conversion actually is worse than keeping the 1234 , as far as idle air performance, now at highway speeds may provide some extra cooling efficiency- my reasoning is the difference in properties of the 2 gases and the installed components that are designed to work with 1234.
The condenser- and heat removal effencieny - the truck’s OE may struggle with 134
The expansion valve is designed for 1234
So with 134 it will be improperly metered for gas flow into the evaporator.
The AC - High Pressure switch- due to the pressure properties of the 2 gases the 134 will read at a higher pressures and the PCM will react accordingly as it’s programmed for 1234, thus also affecting the cooling fan speed when AC is running.
So for me it’s a question of Why would a professional perform this or recommend this conversion- when the performance hit is worse.

I may be over thinking it and may be missing something but my basic knowledge of the system- has me wondering is the conversion worth the penalty hit in performance

I was also wondering why this was performed considering the phase out of 134A & the reasons you stated component wise. Professional side job?

 

[GreyAreaRanger]

As far as the 1234yf type refrigerant, it’s in a family members 2020 Denali and works too damn good in there. If I can get my AC to work half as well as that truck, I’ll be happy. Unless you select an auto setting, no weird changes when you set it and blows frigid air when it’s hotter and muggier than satans butthole out.

 

[Lablanca2019]

The true test to see what is going on - is to either hook up a gage set or pull up the AC Pressure PID and record the pressure at idle and driving.

From the 1234 Chart @ 100-105 Deg and 15-40% Humidity - the pressure should fall in the range of 260-274 PSI @ idle and a slight pressure drop of that reading when driving (est 20-50 psi) if i recall correctly
another important PID is the Evap Temp - should be about 35 deg - with Max AC
and then the clutch engagement PID or Compressor PID - tells us if the clutch is disengaging
AC Clutch Engaged- True or False (PID)

These 3 PIDs alone can help see what is happening.

since we have a Variable Displacement compressor, could it be possible that its not up to the task at high fan speeds vs low?, Also i do have forscan and have been looking at pressures but let me add the other pid's to the live data feed and see that pops up, sidenote I did look for the evap pid but couldn't find it may have just not looked for it on the correct section thank you the help

 

[airline tech]

Evap Temp = Is under the FCIM

As far as the variable ac compressor - the main factors are:
Outside Temp - Selected Temp - AC Pressure (PID) - and Evap Temp (PID)

The compressor has the ability to produce the cooling even at idle - provided the system charge pressure is within normal parameters - this pressure ties in - condenser (heat transfer) and the Evap Temps

So for a system that has been converted - and still using factory installed components - I think the system pressures are altered enough that the PCM control of the compressor are thrown off and the Evap is not getting the proper metered flow.

Also - was the system charged - with the exact amount as listed on the label, R-134A may require a slight bit more charge

Its something that may require some digging to see the (internal) specs of the compressor control - What are the Low and High Pressure thresholds before the PCM reduces the output and or cutout of the clutch?
I feel this is what the system is fighting (converted) its looking for normal pressures and they may be different with the (conversion) - the PCM does not know its a different gas, its only looking at the pressures and the temp at the Evap as a feedback of its operation

 

[Lablanca2019]

I have an xl would I still have a evap temp sensor?

Evap Temp = Is under the FCIM

As far as the variable ac compressor - the main factors are:
Outside Temp - Selected Temp - AC Pressure (PID) - and Evap Temp (PID)

The compressor has the ability to produce the cooling even at idle - provided the system charge pressure is within normal parameters - this pressure ties in - condenser (heat transfer) and the Evap Temps

So for a system that has been converted - and still using factory installed components - I think the system pressures are altered enough that the PCM control of the compressor are thrown off and the Evap is not getting the proper metered flow.

Also - was the system charged - with the exact amount as listed on the label, R-134A may require a slight bit more charge

Its something that may require some digging to see the (internal) specs of the compressor control - What are the Low and High Pressure thresholds before the PCM reduces the output and or cutout of the clutch?
I feel this is what the system is fighting (converted) its looking for normal pressures and they may be different with the (conversion) - the PCM does not know its a different gas, its only looking at the pressures and the temp at the Evap as a feedback of its operation

 

[RangerBill]

I have an xl would I still have a evap temp sensor?

Yes, you do.

 

[Lablanca2019]

Yes, you do.

Unfortunately the fcim is empty

 

[RangerBill]

Unfortunately the fcim is empty

Are you using the recommended Forscan OBDII adapter?
Try deleting your vehicle profile in Forscan and then reconnecting and create a new profile.

 

[Lablanca2019]

Are you using the recommended Forscan OBDII adapter?
Try deleting your vehicle profile in Forscan and then reconnecting and create a new profile.

Vlinker FS

And I already deleted and rescanned new profile

 

[RangerBill]

Vlinker FS

And I already deleted and rescanned new profile

That may be the reason for not seeing the FCIM module. Forscan web site recommends the OBDLink EX USB adapter.

https://www.obdlink.com/products/obdlink-ex/?ref=forscan

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