ac compressor connections for 328

aren't they a different size?

 

I assume you installed new hoses? Otherwise they would be difficult to re-connect in the wrong location. The outlet of the compressor - could be stamped "outlet," "discharge," or something similar - feeds directly to the condenser. SO if you can determine which hose goes from the compressor to the condenser, connect that one to the discharge side of the compressor.

When you say it won't take a charge, are you trying to charge with just a can of refrigerant feeding directly into the system or using an AC gauge set?

 

The discharge / outlet side is the high pressure side. Be CAREFUL you do not connect the can of refrigerant to the high side - that could cause the can to explode!

 

1988 328:
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discharge / outlet side = high pressure side
suction / inlet side = low pressure side
Sorry if this seems basic, but you've got the high-low pressure switch jumped so the AC compressor clutch is engaged and running the compressor while you add refrigerant to the low pressure side?

 

The compressor clutch must be engaged and compressor turning to accept fluid. Your high and low gages will tell you the rest.

 

You can also use a spare battery (lawn mower) to power the ac clutch without opening up the front bonnet.

 

The high-low pressure switch is located on top of the dryer under the front bonnet -- item 2 in this 328 SPC figure:

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/328-group/328-1988/air-conditioning-system.html

Unplug the connector and use a jumper wire to connect the CN (orange-black) wire in the wiring harness to the VM (green-brown) wire in the wiring harness to simulate a closed high-low pressure switch.

 

Before committing to any "engineered bypasses" of the system's low pressure cut-out safety equipment......is the system in a vacuum?

The presence of a vacuum, coupled with the refrigerant can's pressure SHOULD fill (at least) the low pressure side with SOME refrigerant.....until the pressures equalize. The pressure might be enough to reset the pressure cut-out and allow you to start the compressor.

Putting your can of refrigerant in some hot water for a short time to raise the content's pressure helps too. Plus, you won't slug any liquid through the compressor and mess up it's valves

Jumpering out the safety and running a "dry" system could possibly damage the compressor.

If you already have a deep vacuum on your system and you still can't get a charge (or at least SOME transfer)....the Schrader valve might be fubar and it's core might need replacing. Easy fix for that.

 

One other thought came to mind. Check the end of the gauge hose that you're connecting to the system. Is there a brass pin located inside?

These pins are there to depress the Schrader and open it up. I've inherited gauge sets from guys who have removed those for better flow (they were using them on a different type of valve).

Check both sides of the hose, too. Sometimes hoses are hooked up backwards to the gauge manifold.

 

Autozone and other auto parts stores will loan you a vacuum pump for free. I highly recommend drawing a vacuum on the system first. If it doesn't hold, you can find the leak prior to wasting a bunch of expensive R12 not to mention its the proper technique for best performance.

 

Once you pull a decent vacuum on the system (hook the yellow hose to the vac pump and open BOTH valves on the gauge set) you should be able to put your R12 into BOTH the high side and the low side of your system. This is while the system is OFF.

Its ok to get some liquid R12 in the low side (or suction side). The stuff will eventually flash off into a gas which is fine. You want that. If you start the system with liquid on the suction side, you'll slug some liquid into the compressor and MAYBE bend the valve. Just take it slow and if you think you added some liquid refrigerant to the low side.....give it 30 minutes to flash off to gas.

Remember....the system integrity MUST be maintained. Don't let any air into the system. Close off all your valves before moving on to your next step. Just take your time.

Sorry for the long posts....this is the Refrigeration Tech in me and instructor coming out.

 

Here are my pics showing the suction & discharge marks if that helps. '87 328.

Craig
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