Ls-1 a/c compressor questions

[956LOUIE]

The original a/c compressor for an ls-1 engine constantly runs not cutting off which freezes the ac lines and compressor burns out. Is there something that is used to make the compressor cut off ? Or what type of compressor can be used i really wanted to use the original 5.3 compressor

1957 chevy ls-1 w/standalone wire harness

[blackdiesel]

Call vintage air or what ever kind of air you have, and get it straight form the horses mouth. I'm running the stock compressor with mine, but don't take my word for it. you can ask 10 guys and get 10 different answers.

[tmoble]

you need a thermostatic control switch in the power feed to the compressor clutch. These have some type of temperature sensor in or on the cold air side of the system. some guys try to do this with a pressure switch but you'll get a lot more cycling with a pressure switch.

[MrDude_1]

Originally Posted by 956LOUIE

The original a/c compressor for an ls-1 engine constantly runs not cutting off which freezes the ac lines and compressor burns out. Is there something that is used to make the compressor cut off ? Or what type of compressor can be used i really wanted to use the original 5.3 compressor

1957 chevy ls-1 w/standalone wire harness

what kind of standalone wireing harness is it?
if its an aftermarket PCM, your SOL and have to rely on old style pressure switches.

if its a stock PCM and just an aftermarket harness, you can add the two wires for the computer to control AC relay.. this is ideal as the PCM knows how fast the engine is spinning and can disconnect the AC compressor at high RPM (one of the things that kills them).. and the PCM can read the current AC system pressure, and cycle it appropriately.

same thing goes for the fans... and trans... and everything else the OEM PCM was connected to.

[956LOUIE]

It is not an a/m pcm it is an oem pcm so that means i can get a scematic and run the wires so the pcm can read the a/c system presure right ?

[956LOUIE]

This is the engine

[RootBeer 6117]

I will throw my .5 cents in, most GM AC systems have a low pressure cut of switch located on the receiver dryer under the hood next to the right side fire wall it cuts off the AC compressor to keep it from burning up. I looked at the diagram for a 2004 5.3 it shows one on the system. You could easily get a low pressure switch from a parts store and wire it to the AC relay to shut off the compressor when the pressure drops below 20 psi. Most of them screw on to a port on the REC. DRYER.

[Kid]

Originally Posted by blackdiesel

Call vintage air or what ever kind of air you have, and get it straight form the horses mouth. I'm running the stock compressor with mine, but don't take my word for it. you can ask 10 guys and get 10 different answers.

I'm running stock compressor & vintage air too, no problems...

[tmoble]

>>> "i can get a scematic and run the wires so the pcm can read the a/c system presure right ?"

you would also need the sensors the CPU is reading. they'll be located somewhere on the plumbing of the OEM system.

[MrDude_1]

Originally Posted by tmoble

>>> "i can get a scematic and run the wires so the pcm can read the a/c system presure right ?"

you would also need the sensors the CPU is reading. they'll be located somewhere on the plumbing of the OEM system.

yep. its a 3 wire pressure sensor located next to the drier in every GM application ive seen.



In a unrelated note, when tuning OEM cars, I hook the wideband O2 sensor output to this AC pressure input.. that way i can log the "AC pressure" and actually log the wideband in sync with the PCM.
I wrote an article about this back in 2006 You can read it here.