Automatic Speed Control on 81 - 83 SCs
 

Looking on page 971-4 of the Bentley I see that the front relay panel on the 81-83 SCs have and "automatic speed control" relay in the #4 position.

What is that exactly?

Does cruise control have a relay? Or, did Carreras have one, and Bentley maybe is wrong for SC? I think later Carreras had an electronic CC instead of vacuum, and it may be for that.

You'll remember my other thread (http://forums.pelicanparts.com/porsche-911-technical-forum/581935-what-would-cause-sudden-rich-condition.html).

It turns out that the decel valve was causing the major idle surge. Well, the decel valve routes to the cruise control servo. And while I was installing my H4 relay kit I removed and reinstalled that "automatic speed control" relay (just to free up some room to get my hands in there to tie in the new wires). So if the "automatic speed control" relay is somehow tied to the cruise control, my problem may actually be there instead of the decel valve.

Just trying to determine what that thing does.

Pull it and go for a ride!

Oh I'm doing that!

But still ... gotta know what it is / does.

Anyone? I can't find any info.

Go for a drive with the relay removed, and try to use the Cruise Control.

If it doesn't work, put the relay back in and go for a drive and try to use the Cruise Control.

If it works again, then . . . . .


(I know you know this, just having fun.)

Yes yes. I hear ya.

At least your are helping me bump it to the top.

Someone HAS to know the purpose of the relay. It may not have anything to do with the cruise control.

Cruise control motor.....
 

Craig,

The round relay you removed is the cruise control (Tempostat) motor relay. Removing it would disable the cruise control motor!!!!! Did you plug the vacuum line from the cruise control to the decel valve when you detached it? Keep us posted.

Tony

An answer! Thank you!

My cruise control has never worked in my 6 years of ownership. Never cared - never used it - don't plan on fixing it.


I'll answer this on my other thread just to keep the two separate.

Thanks!