No power to AAR - where to start?

[LeeH]

My '72 w/'82 3.0 has had a creeping idle problem. I tested the AAR today. While it was idling high I pulled the exhaust side of the valve and verified that it was not closing.

There was no power to the plug. I jumpered 12V to the AAR and it slowly closed. So... it definitely looks like the problem is electrical and not mechanical. However, the wire that goes to it runs to a harness I can barely see - let alone touch. Any suggestions on how to track the problem? Where would I find the other end of the wire that goes to the AAR?

[Elombard]

I had the same problem on my 73 with SC motor. I bet the WUR is not getting power either, they are on the same circuit. It will run MUUUCH better when you get power to them.

The 14 pin plugs come apart and you can see the wire colors in them. They are differnt for the years. Search pelican for the Sc wiring diagram. The Scs were pretty much all the same. Then find a female socket that has key switched on power and move the pin for the AAR/WUR to that socket. I had to jumper a relay to get it all to work, for some reason the relay was not operating and bringing power to the socket. Anyway hopefully you can find a socket that is currently not being used. Hopefully some one that has done the switch n your chassis can give you actual wire colors pin numbers etc.

The bottom line is the the AAR and WUR need power when the key is on. Make it so!

[wswilburn]

On my 1982 SC, the wire is red w/ white stripe and connects to pin 10 of the 14 pin connector. On the chassis side, it connects to pin 30 of the fuel pump relay.

[LeeH]

This is strange... both of the two wires that go to the AAR seem to be grounded. How can that be? I tested both contacts and I get continuity to ground. Does that mean I have a short?

[2.7RACER]

Lee,
This is the schematic of your '82 SC showing the AAR and WUR.

Please note, both are wired in parallel to pin 30 of the fuel pump relay.
The terminal just above both is T10-14. I think this is the 14 pin plug.
I would pull the 14 pin plug from the motor at the corner and trace the wires. I suspect pin 14 goes to both the AAR and WUR.
The corresponding end in the corner at pin 14 should read 12 volts with the ignition on.
The 12 volts at pin 14 with the ignition on would come from the fuel pump relay pin 30.
Possibly a broken connection at the 14 pin connector, either end, or at the front of your car, at the fuel pump relay.
Good luck,

Edit: I incorrectly read the schematic for the terminal above the AAR and WUR.
It should read Terminal 14, pin 10. not terminal 10 pin 14.
Any reference should read pin 10 not pin 14. Pin 14 is hot all the time. Pin 10 is the correct pin for the control voltage to the AAR and WUR.
Sorry for the error.

[Mysterytrain]

WOW..looking at the schematic and the light in my head went off. The WUR resistance and the AAR resistance are in parallel. So one effects the other! Maybe thats why I've seen some WUR's with a set of contacts inside???

Without power being applied to the circuit both AAR terminals will look like ground..one at zero resistance and the other will be something close..17 ohms or so. Look at the wiring diagram.

[Elombard]

Doug you the man!

Ron I have no idea what you are saying but I will trust you :-)

I remember a few people that have removed the AAR from there car. Then they have to go make the WUR adjustable. I wonder if this is why?

[2.7RACER]

I just found out I read the terminal wrong. It's terminal 14, position 10, not T10 pin 14. Makes more sense now. Sorry for the bad interpretation.

[2.7RACER]

Here is a closeup of Terminal 14, pin 10.

[Mysterytrain]

If you are using an audible beep to ck the circuit ..like the fluke meters have or you are on a high range scale then placing one lead on the red/white wire at the AAR and the other on the chassis will look like a ground..and give you a beep. The reason is the path to ground goes thru the heating element on the WUR which is only 17 to 25 ohms. you would have to disconnect the connectors from the WUR and the AAR to trace the wire properly. Clear as mud?

[LeeH]

Problem solved. Thanks for the guidance. As you can see, the wiring on the engine swap is OK, but could be neater. While poking around I happened to see a red/white wire that was in the hole next to the yellow wire in the photo. I fished it out and found it wasn't connected to anything.

After testing for continuity to the #10 pin I jumpered 12V to it and watched the AAR close. I attached it to the defroster fuse since it's switched, went for a drive and enjoyed a perfect idle. I don't know if that wire just got missed, or if they thought it wasn't needed.

[cmonref]

2.7Racer: Isn't your "terminal 14, position 10" actually "pin 10 of a 14-pin connector"?

[2.7RACER]

Brian,
Yes it's pin 10 of the 14 pin connector.
The schematic as shown on my previous post refers to the 14 pin connector as Terminal 14, or T 14.
I originally picked it up as T 10 pin 14. My error.
Deciphering some of the code used with these schematics can be challenging.
But the knowlege obtained from becoming familiar with the various schematics makes troubleshooting much simpler.
I still struggle with some of the early schematics, simply because the entire electrical system is on one page. The components are placed somewhat close to where you might find them in the car, along with a maze of wires, which require very careful tracking to get to where each wire goes.
That said, the later current flow diagrams are made as multiple pages, which means flipping from page to page seaching for the ultimate destination of each wire.
I have successfully printed the multi page schematics and the taped them together into large E size drawings, which makes tracing the wires much easier.
The same with the early car schematics. Once the size is enlarged to D size or even E size it become much easier to work with.
Hopefully, I can get some of these larger schematics copied to share with fellow Porsche enthusiasts.

[acapella8]

If you get some of the larger schematics copied -- I would love to be on your mailing list. Acapella8@aol.com - Thanks Doug!

Tom

[cmonref]

2.7Racer:

What a great idea, printing in D and E sizes. I can see it as wallpaper for the garage.

But then I would have to move everything to the center of the floor ....

Brian