oldgoat69

I am finally ready to get the A/C working in my 69 GTO after poaching myself on the way home last weekend. Does anyone have a picture of the correct hose routing, and any additional parts required? I have factory A/C in the car, and the compressor from the LQ4. I had the POA valve rebuilt a couple of years ago, and a new condenser. I appreciate the input in advance.

ls1nova71

iTrader: (4)

I would ditch the POA valve and go with an orifice tube style evaporator, like the newer systems. Less parts to go bad and POAs don't seem to work as well with 134a. Also if your condenser isnt a parallel flow, id change that too even if it is new. That's just my opinion though.

rockytopper

You can convert the poa to a cyl system with one of these kits. Several venders sale these if you plan to just run it direct and not thru the pcm.
http://www.oldairproducts.com/catalo...it-p-3672.html

I didn't replace my condensor but I have also been told if I replaced it with a R134 condensor my system would improve.

oldgoat69

I bought an R134A condenser when I replaced the original. I had the POA recalibrated for R134a at the same time. If the unit you show works better I am all ears. I do need to see a hose routing if anyone has photos or a schematic.

BP Automotive

iTrader: (3)

Here is a simple wiring diagram for the lsx wiring aspect. If you use a high pressure switch along with a low pressure just wire the high pressure switch in line with the low pressure on the A/C request to the compressor relay.

ls1nova71

iTrader: (4)

Hose routing is pretty straight forward. From the compressor discharg (high side, smaller line) to the upper side of the condenser. Bottom line out of condenser to the orifice tube in the lbottom line into the evaporator, top line out to accumulator, and then from accumulator back to the suction side of the compressor ( bigger line).

oldgoat69

ls1nova71, you confirmed my suspicion regarding plumbing, I could not remember how the original was setup.
BPautomotive, I planned to use the original 69 controls, not run through the PCM. Does this still require the low pressure switch? Can I use the OE poa?

bczee

iTrader: (12)

Old Goat.. Not sure if this what you trying to do.

But I left my complete 71 OEM AC unit in place and only replace the Compress with the LS1 one and had my line/hoses modifed for the correct ends and lenght to adapte the LS1 compressor. I know it is not the best setup. .as with the Variable compressor, the system is degraded in slow or bumper to bumper traffic.. but once moving, it stay around 48-50 degress on the output air.

I know I shoud most likely replace the front Condensor and do change the POA. I am also using something they call Duracool / 12a...

BC

BP Automotive

iTrader: (3)

In the diagram I posted the PCM is not controlling the A/C in anyway whatsoever. The Lt Blue A/C request wire is the 12v signal to your compressor relay from your A/C on switch/thermostat. The low or high pressure switches just simply kill the 12v to your compressor relay.

The single wire that goes back to the pcm is just so the pcm knows the compressor is pumping. Then the pcm will kick the fans on and bump the idle up.

67Skylark

The single wire that goes back to the pcm is just so the pcm knows the compressor is pumping. Then the pcm will kick the fans on and bump the idle up.[/QUOTE

"The single wire that goes back" Is this possible on the E38 PCM, if so what pin?

oldgoat69

BC, this is exactly my plan.

oldgoat69

Well after killing one compressor due to my own stupidity, I am making some changes. The original POA is being replaced with the pressure switch mentioned above and a new compressor has already been installed. This time I have added the correct amount of oil directly to the compressor. I will also evacuate the system prior to charging. I hope this is the last time I need to touch this.