Almost done with A/C.

[Nick Triesch]

Everything is back together. I put in as much refrigerant as I could with compressor clutch not starting. Bummer, the clutch will not start! Could someone please tell me what connection to use to bypass the relay to get the compressor running? Everything was working fine before I took it apart. BTW, the AC blower works just fine. Clutch just will not kick in. If I could get it started then I could add more refrigerant to keep it going.

[Ronnie's.930]

Nick, have you verified that the power wire to the clutch is not showing voltage?

When you had the system apart, did you have the a/c mounting brackets powder coated? I ask, because I did this many years ago, and then needed to add a ground wire from one of the bracket mount bolts to a fan shroud bolt in order to get a good ground so that the compressor clutch would engage (could have taken the brackets off and done some sanding, but adding the ground wire was much easier, obviously).

Also, try taping the a/c relays with a screwdriver handle or the like - key on / a/c on. If the points inside are stuck, taping the case can jar them loose (like Karl just experienced).

[Nick Triesch]

OK Ronnie, I'll try that. But also I heard that you can take the relay out and jump two connections to get the clutch going. Thanks.

[GH85Carrera]

If your system is stock there is no pressure relay. If you did a conversion to 134a you should have had a pressure relay added.

Tell us more about your system? Is is 100% stock or a custom system you built?

[Nick Triesch]

System is all stock.

[Nick Triesch]

Switched over to 134a

[GH85Carrera]

Unless you or someone else added a pressure switch, you don't have one. The factory did not add pressure switches in the AC system for the SC or Carrera.

You might check the AC relay up in the smugglers box. You need to find out why you don't get 12 volts to the compressor clutch.

[Nick Triesch]

OK, thanks. The crummy thing is it was working fine before I took it apart. Just leaked at the shaft seal. Replaced it and put it back together. Did nothing to the electrical parts.

[targa80]

I used 12 volts from the power panel in the engine compartment and jumpered it to the connection going to the factory A/C clutch because it was not engaging on initial start up. This allowed me to continuing to charge the system under pressure from the compressor. after the second 12 oz. can was in I was able to run the clutch normally.

[Nick Triesch]

I'll try that Pat. If I cant get it going then it was something I did during assembly. But there is not a lot that can go wrong.

[Nick Triesch]

It should go on. The blower works fine , My 409! OH OH....I'm starting to snap! And it is 90 outside!!!!

[Ronnie's.930]

Nick, is the compressor properly grounded? The clutch will not engage, otherwise (despite having 12v at the power wire).

[Nick Triesch]

Well, it put back just like it was in it's brackets. I cleaned the brackets before I installed it and hooked up the same wires. Everything seems toght and clean. Some guys say there is no pressure switch so it should come on.

[Ronnie's.930]

Nick, can you verify that there is no pressure switch that a previous owner might have installed? It would be located in the high side hose between the compressor and the tail condenser, or on/near the dryer.

They look like this (in case you are unfamiliar with them).

Amazon.com: Santech Air Conditioning Pressure Switch: Automotive


*** Duhhhhh on me - if the hot wire to the compressor is hot when the system is empty (you said it was), then there is not a pressure switch in line.

Something is causing the compressor clutch to not activate or it's sticking. Try taping on it while key and a/c controls are on.

[Nick Triesch]

No pressure switch that I can find. I installed new dryer. I'll try tapping the compressor. They arte built like a tank!

[DaveMcKenz]

Bad clutch?

[Nick Triesch]

OK here is the good news and the bad news. After all my work replacing the shaft seals and all the other stuff. I finally got the clutch to engage by tapping with a rubber mallet. Thanks Ronnie! The bad news is that after I took the car out for a spin I noticed the very thin oil film up on the back engine lid. When I installed the new seal kit they went in very nice and both were seated. I hate to say it but griff was right... After 30 years these old Nippondenso compressors are done. I am bummed but I have a coffee can to put cash in once a week for a rebuilt compressor. On the plus side I learned a heck of a lot and had fun. That is why I have this old 911. Also I have had a lot of wins..fixed speed control, headlight washers, fixed my drivers door and a bunch of other stuff. So, there you go. Nick

[crownarch]

Nick, at this point you are going to have to determine how catastrophic your compressor failure was. You definitely want to determine whether your system has experienced the dreaded "Black Death" failure. I am assuming that since you installed a new seal in your compressor that it has failed previously. And assuming that you had these two compressor failure's you need to investigate further. If you are not familiar with the term "Black Death" in a/c systems you can Google it and learn what it is. I say this, because I just had this occur in my system earlier this year and had to decide whether to start replacing some a/c hardware and/or what required flushing out. Hang in there guy, it can only get better as you will just keep learning.

[Nick Triesch]

The stuff coming out of the lines did not look all black and horrible. Just the end of the line for my compressor. Come to find out, they used that same model in a lot of other cars. I should be able to pick one up for $800 or so!

[DaveMcKenz]

I found a nice re-manufactured one on ebay for $229 shipped.
Good luck,
Dave