CIS & Vacuum Line Routing
 

In my quest to get my CIS in top shape, I have replaced all the vacuum lines (or at least most of them) as well as fuel injector seals, manifold gaskets, etc.

As I progress, I use the PET catalog as a general guide to identify parts. In the process, I noticed that my large vacuum line coming from the WUR is routed completely differently from the PET diagrams.

My WUR has two vacuum lines and the larger line coming from the top is routed and merged with the tiny line coming out of the top of the vacuum limiter. The PET show two scenarios; one routed to the bottom of the throttle body and one to a thermal valve, which my car doesn't have.

My car is a '74 with '76s injection and a '79 fuel distributor (per the prior owner and mechanic that built the engine).

Question: should I re-route this line so that the vacuum source is from the bottom of the throttle body, or should I add a thermal valve, or is it ok as is (merged into the very small line of vacuum limiter).

any advice would be appreciated - I know there are many CIS experts on this board.

Thanks......Vern

the thermo valve (TTV) is for making it run richer when cold. if you live up north, it is a "nice to have" part.

you need to post the part number off the WUR. some had the vacuumport on top, some had it on the side, or bottom.

you can figure out which one is the vacuum port by connecting each one to manifold vacuum. the one that changes fuel pressure, or makes it run different, is the vacuum port. it should be connected below the throttle plate.

the other is just a vent. connect it above the throttle plate.

i am not sure what you are calling a vacuum limiter

I'll get the part number later today for my WUR (I may need a magnifying glass). The vacuum limiter is the part that is right next to the throttle body and has vacuum to the bottom and from the top. My WUR is currently "tee'd" into the top, very small, vacuum line. My WUE also has the small side port which is connected to the top of the throttle body.

MY WUR - Has two ports (one large on top, one small on right side - can't be seen in photo):
http://forums.pelicanparts.com/uploa...1324055789.jpg


Vacuum Limiter - where my WUR is tee'd into: (just next to throttle body)
http://forums.pelicanparts.com/uploa...1324055843.jpg

From what I can see in the zoomed photo, my WUR's part number is: 436.140.033 it also has 930 stamped on the left top.

that is a decel valve. i figured that was what you might be talking about.
the WUR should be tied into that.
it looks like you are plumbed properly.

pull the vac line off the WUR while it is running. it should change how it runs, it may even stall out. easy check to verify it is working.

Go here:

WUR photo

Scroll to the bottom of the page. The one on the left is the 033. The port labeled "manifold" is the vacuum port, the one labeled "atmospheric" is the vent.

Jim,

You are great! And thanks for your other posts today - they helped a lot.

Vern

Please clarify........
 

Jim,

Looking at the WUR's in your picture, something caught my attention. The WUR shown for '80 SC seems to be not the right one. I believe it should show a -072 type WUR like this:

http://forums.pelicanparts.com/uploa...1324093519.jpg

Thanks.

Tony

Tony,

Check my post #12 on this thread:

http://forums.pelicanparts.com/porsche-911-technical-forum/645280-wur-no-vacuum-whats-nipple.html#post6437399

It shows that there were two versions of the -072. The early one had no nipple; I posted the WUR photo shown on the Primer before I discovered there was a later version of the -072 that had a nipple.

Many thanks.........
 

Jim,

I missed that post about the old/new -072 WUR. And we are grateful for all the good work you have done to keep our CIS cars in good condition. The information you have collected is priceless. Thanks.

Tony