MHT

that wire is NOT a ground wire, it is the power wire to the compressor clutch. If the fuse blows when you hook that up then the coil on your comp. clutch is shorted. The clutch ground is a short wire that connects to the body of the compressor. The compressor is a Nippondenso unit, it is used by various manufacturers, Chrysler, Ford and several others, none of their compressors will work because the mounting points are different, but the clutch parts should work, though you might have to do some minor re-wiring.

Perry 951

The compressor ground is the casing. Since it is connected to the bracket, it is basically grounded to the block.

MHT has it, your clutch coil is probably shot.

stolarzj

I hadn't read in there that he attached it to the high pressure side. In my case, I bypassed it since I had a completely empty system, and reattached the wires after one can was added. I probably could have tried to let the can de pressurize into the system with the system off, but it just didn't seem to be happening in my case. Perhaps I didn't wait long enough..

qoncept944

Anyone have a spare compressor clutch or know a good source or alternative? The rebuild clutches on ebay are pretty steep (ie, more than a used compressor).

Danno

"There is not enough room for the "quick release" end of the fill hose to attach. I think it is the alternator bracket that is in the way."

I think the earlier cars had two ports on both high- and low-pressure lines up on the strut-tower??? The low-pressure is the larger of the two lines.

sm

How difficult was it to replace the expansion valve?

Jeremy Himsel

SM,

The expansion valve is very easy to replace. You can do it from underneath the hood. Remove the blower motor assy.( 6 or 8 small bolts and two plugs) and it's right there on the passenger side of the car. Took me 25 minutes. I've heard stories of guys doing it from inside the car and taking hours.

DanG

Hey guys, I'm a little confused which sensor I'm supposed to jumper and whether its to jumper the two wires together, or one or the other to +12 or ground. The green one on top doesn't seem to have any sort of connector, as if I'd have to clip the wires to be able to jumper them.

Jeremy Himsel

Dan,

On the 86+ cars the lower sensor is the low pressure cut off switch. Many people jumper this one to get the compressor going. The upper switch activates the cooling fan based upon pressure. Why are you jumping the switch?

DanG

Jeremy, I want to jump it because it won't take in any refridgerant. I've tried to refil after having the system professionally pumped out, new drier installed, and then vaccumed down, but the compressor never switched on (I watched and listened for 20 minutes). I want to just override the switch for the first can, then reconnect and let it do its thing.

Also, what is the common opinion on the capacity of the system? 4oz can of oil, then is it 2 or more cans of 134a?

Jeremy Himsel

Dan,

Are you sure your hose is breaking the seal on the Schrader valve? If you have a good vacuum and you are breaking the seal, the first can should get fairly cold as you lose about 6oz of Freon. I recently ran into a situation where the charging hoses I was using wouldn't depress the valve.

On my car (and many others), with the system off (emphasis on "System Off"), I'll connect the hoses to the high and low sides and open the can of freon. This will charge the system up enough (about 30 psi on each side) to start the compressor. Usually 6 to 8 oz of freon will get the compressor to begin cycling (be sure to disconnect the high side hose before starting the car). I've never had to jump a bypass switch to get the system going unless the switch was bad.

As far as oil goes, about 2.5 oz of oil is what system capacity is. If you go over slightly it shouldn't hurt anything. Refrigerant capacity is an odd one on the Porsche as they allow a lot of room for refrigerant loss. The bubbles in the drier usually stop around 24 oz of r-12 freon and provide good cooling. Most 44 shops will charge the system with 26 oz of r-12 and charge you for 33.5. The system should use about 28.5 oz of 134 max so two cans will be enough.

The most important thing when it comes to charging AC is to use gauges. 30 on the low side and 180 on the high side is a good number for our cars will obvious variations for ambient temps. If you really need help with this I'll send you my phone number and you can give me a call.

DanG

Thanks for the advice Jeremy! I'm gonna try the job this evening, I'll attempt your method before I resort to jumping the switch.

DanG

Still no good...

I tried charging my AC last night with the proper method (from another thread) and my compressor still never even attempted to kick on. I think it has to be either the compressor relay or something in the clutch itself.

I'm going to price out a new compressor relay and if its too much, I'll take it to a shop to avoid fixing something that might not be broken.

nh3

You guys had better make sure you flush the system before the conversion. The r12 oil and 134 oil are not compatible and will create an acid when combined. Will eat o rings and seals.

nh3