At a loss! Vin air sure fit gen iv giving me fits

[MAGONSTERZ68]

I hope VINTAGE AIR TECHS have their reader on for this one.
68 Camaro GenIV sure fit system
Using 3 knob billit rotary variable blend / speed/ temp controller and not the original with mods.(does it have to be calibrated to system?)
SD5 compressor
Car utilizes dual electric fans 3000 cfm with trinary switch keeps car steady at 205 in 100 plus degree weather.
Inline aluminum through firewall bulkhead with extended lines routed through fender
Radiator to core support is foam sealed and pulls hard through closely spaced radiator / condenser / trans cooler

1st attempt:
Charged system on 98 degree ambient temperature day
Evacuated with zero problems 1 hr., held vac no prob 1 hr.
Used digital scale to load loaded 1lb 12oz as per instructions.
Charge was loaded with car at 1800 rpm (to simulate cruising speed) 3.42 gears with 26" tall rear tires
Low side was 30, high side was 275, and center vent temp was 62 degrees
line on compressor was cold and sweaty

Second attempt:
Evacuated 45 min, held vac 45 min
Loaded freon until gauges read 12 to 15 psi on the low and 175 to 200 psi on the high at 1800 rpm same 95 degree ambient temps
Line was NOT cold or sweaty
center vent temps never dropped below 80 degree.

Third attempt:
utilizing second attempt continued to load feaon utilizing gauges read 30 psi on low and 275 on the high again
temps dropped back down to 62 degrees, line was cold and sweaty.

At one point i pinched off the hot water in line to the core to verify i was not getting hot water bleed by into case, no change in temps whatsoever.
On all three tests i sprayed water at condenser, head pressure would drop and low side would follow suit, it would cycle out and recover to high low as before.

Really starting to wish i had gone with a different manufactured system at this point.
Any clues where to start?
Used autozone freon stuff with oil and dye mixed in with it if that is of any difference.
Thinking i might vack the system flush drier and condenser and reload with JUST freon with zero additives such as dye, oil or seal conditioner.
:banghead:

[GoodysGotaCuda]

Have you tried different gauges to validate the pressure readings?

The pressure differential should make the temp drop regardless unless you just cant get enough volume of refrigerant through the evaporator for some reason. Like a choked up expansion valve or something.

You likely have enough oil in the system, only use straight R134a, in my opinion.

[cpd004]

My system has a warning to not add any oil. It only calls for Freon. The correct amount of oil has been added from the factory.

[Dark Pursuit]

Like cpd004 said above, sounds like too much oil..Your compressor should have come already filled.

[dhutton]

Like cpd004 said above, sounds like too much oil..Your compressor should have come already filled.

Yep VA compressor is precharged with oil. Do not add oil....

Don

[oleyeller]

Have you verified that the controls are working properly? Have you verified the heater valve is installed in the correct direction, and your damper doors are in the correct position for cooling? You could be mixing hot and cold air and not be straight cold. I would re run the calibration process for the controls.

[MAGONSTERZ68]

Have you tried different gauges to validate the pressure readings?

The pressure differential should make the temp drop regardless unless you just cant get enough volume of refrigerant through the evaporator for some reason. Like a choked up expansion valve or something.

You likely have enough oil in the system, only use straight R134a, in my opinion.

have not verified against a different set of gauges yet.
will try evac and fill with straight R134a next.
thx

[MAGONSTERZ68]

Have you verified that the controls are working properly? Have you verified the heater valve is installed in the correct direction, and your damper doors are in the correct position for cooling? You could be mixing hot and cold air and not be straight cold. I would re run the calibration process for the controls.

using the billet 3 knob rotary, variable controller all seems to work as it should, do not believe these require any kind of calibration, plug and play, unlike if i were to utilize the original lever system with the conversion kit.
the heater valve is verified correct flow as well as proper flow from the water pump outlet.
156309

[ULTM8Z]

I'd start from scratch...

Don't re-use the drier, get a new one as theyre dirt cheap on ebay. You're generally not supposed to flush these things.

Given how many evacuations and refills you're done, I'd try to empty as much oil out of the compressor as you can.

Then flush everything individually... hoses, condenser, and evaporator. Remove the expansion valve though... don't flush with this still installed and don't attempt to flush it at all (don't want any debris getting in there).

Then re-add the correct oil to the compressor.

Then reassemble the system. Evacuate it and leave it sit overnight to verify no leaks (may seem excessive, but let's be conservative here).

Then refill the system per vintage air instructions, using only 134a (no oils or dyes).

[MAGONSTERZ68]

I'd start from scratch...

Don't re-use the drier, get a new one as theyre dirt cheap on ebay. You're generally not supposed to flush these things.

Given how many evacuations and refills you're done, I'd try to empty as much oil out of the compressor as you can.

Then flush everything individually... hoses, condenser, and evaporator. Remove the expansion valve though... don't flush with this still installed and don't attempt to flush it at all (don't want any debris getting in there).

Then re-add the correct oil to the compressor.

Then reassemble the system. Evacuate it and leave it sit overnight to verify no leaks (may seem excessive, but let's be conservative here).

Then refill the system per vintage air instructions, using only 134a (no oils or dyes).

exactly where im leaning to at this point.......thx

[ULTM8Z]

I wonder if somehow your expansion valve is malfunctioning or something??

[MAGONSTERZ68]

I wonder if somehow your expansion valve is malfunctioning or something??

Im going to replace drier, flush condenser, unplug the heater lines (just inc case), and charger with straight R134a n see what happens.

[dontlifttoshift]

I wonder if somehow your expansion valve is malfunctioning or something??

That would show on the gauges.


Im going to replace drier, flush condenser, unplug the heater lines (just inc case), and charger with straight R134a n see what happens.

Start by just pinching off the heater hoses and see what you get for vent temperature. One thing at a time, let's be methodical.

[MAGONSTERZ68]

That would show on the gauges.



Start by just pinching off the heater hoses and see what you get for vent temperature. One thing at a time, let's be methodical.

Does anyone know if the VA Slimline 3 knob variable controller require calibration? I cant find any literature from manufacturer to state either way yes or no.
Will attempt to calibrate, then disconnect heater hoses and see what test.
156320

[dontlifttoshift]

It does not require calibration assuming it was ordered at the same time as the unit. If it was, the unit then came with the correct ECU which does not require calibration.

That control panel will not work with any unit that was originally equipped with a conversion kit for your factory controls.

[ULTM8Z]

The other thing you want to ensure is that the fan isn't pulling air from around the condenser instead of through it. The condenser should be in front of the radiator and sealed to the radiator support as much as possible that way air is forced to go through it.

[MAGONSTERZ68]

The other thing you want to ensure is that the fan isn't pulling air from around the condenser instead of through it. The condenser should be in front of the radiator and sealed to the radiator support as much as possible that way air is forced to go through it.

great point, it was one of the first things i did, spaced condenser bracket closer to radiator, then completely sealed radiator to core support with dense pvc foam for maximum 3000 cfm pull through rad and condenser, no improvement unfortunately but at least eliminated that possibility, thx

[MAGONSTERZ68]

It does not require calibration assuming it was ordered at the same time as the unit. If it was, the unit then came with the correct ECU which does not require calibration.

That control panel will not work with any unit that was originally equipped with a conversion kit for your factory controls.

yes, purchase units at the same time, results when tested it controls all as it should be with the possibility was not fully closing hot water valve but Vents, heat/cold, fan speed, is fine, just does not get below 60 :/

[MAGONSTERZ68]

well it only been 6 yrs and 8 months but finally have cold air, down to 45 degrees. Of course it on the 3rd engine and runs like a champ so now focused on A/C, ended up swapping in an SD5 to work off of rear single belt, new drier and expansion valve, started with 1.5 lbs bled off till low side was 35 and high 225 in 78 degree weather, center vent was 44 degrees so i called it good. Im pressure sure i had either waaay too much oil in system and or faulty expansion valve, either way not im munny! Sure fit system for my 68 rag top, some say 35 is high and may experiment later with bleed down to see if 25-28 brings temps down but calling it a win for now as rag top in 100 degree weather is tough to cool anyway.