HELP,CIS problem
 

HI,I am putting my 1974 911 2.7 CIS back together and have a small vacuum switch(has 2 contacts on it to power it up)that is fitted in a vacuum line that comes from the throttle body down to the warm up regulator.I would like to know how it works and what it does and how to wire it up.thanks in advance.Alan

How it works: It is activated when you pull the hand throttle all the way up. This has the WUR send extra fuel for when starting a cold engine....

I think what you are talking about is the thermotime valve...at least that is what I have on my 78. Basically, it is a time controlled valve that prevents vacuum from going to the WUR when you first start the car.This allows the car to run a little rich during the start up phase. Once the heating element gets hot enough it opens the valve and allows the WUR to lean out the mixture at idle or high vacuum conditions. When you open the throttle that vacuum line now serves to enrichen the mixture.

http://forums.pelicanparts.com/uploa...1150120397.jpg

You're right Ron....I was thinking of my '73 that has a "cold start" valve, which is different than an WUR.....

OK,but looking at the pic my vacuum vavle is plumbered to the top outlet
on the warm up regulater,will this matter??

bump

http://members.rennlist.com/jimwms/CIS/CIShome.html

If you click on the CIS Components link and then scroll down to Control Pressure Regulator section you can read all about them and then click on the link..it will take you to a group picture of the WUR's. Yours is the first one shown on the far left. Scroll down to the last picture and you will notice the different positions for the vacuum [manifold] connection and atmosphere on the 77 version and the 78/79 version.