Warm Up Regulator Vacuum Line

[DienstXIV]

Hi everyone I have a 1975 911 S and here is my situation:

The car has a high idle when warm and when the engine is cold it will start but will not stay running unless I hold the RPMs up with the gas pedal.

I noticed a few vacuum lines have been tampered with and I would like to figure out how to get everything hooked up correctly. My biggest question is I have a vacuum controlled Warm Up Regulator but it's not connected to anything. I hear it should connect to the intake manifold but where? I cannot find the port for it. I have a picture attached.

Also a vacuum line going from the intake manifold to the distributor is also cut and plugged with a screw, does anyone know why someone would do that?

Thanks in advance!
Alex

[Flat6pac]

The vacuum line to the distributor is a vacuum retard emission control
If it’s hooked up properly it vacuums the distributor several degrees ATDC and lowers the RPMs
It has to come off a port below the butterfly so it has idle vacuum
There is vacuum ports to the rear and to the front of the TB I think the one on the back is below the butterfly. Check, hook a hose and run it to your tongue you’ll feen the vacuum
Bruce

[DienstXIV]

Thanks Bruce! I felt all around the Throttle body and I cannot find an empty port on the throttle body. There is a vacuum line that goes from the intake around the back of the engine to either the oil tank or oil filler should I get a T fitting and connect the Warm Up Regulator vacuum line to that line?

[boyt911sc]

Originally Posted by DienstXIV

Hi everyone I have a 1975 911 S and here is my situation:

The car has a high idle when warm and when the engine is cold it will start but will not stay running unless I hold the RPMs up with the gas pedal.

I noticed a few vacuum lines have been tampered with and I would like to figure out how to get everything hooked up correctly. My biggest question is I have a vacuum controlled Warm Up Regulator but it's not connected to anything. I hear it should connect to the intake manifold but where? I cannot find the port for it.I have a picture attached.

Also a vacuum line going from the intake manifold to the distributor is also cut and plugged with a screw, does anyone know why someone would do that?

Thanks in advance!
Alex

Alex,

Where is the picture? You could get a vacuum line from the decel valve (top or bottom) for your WUR. Adding a thermovalve in your ‘75 CIS would improve the cold start idle.

Tony

[DienstXIV]

Hi Tony,

I don't think the attachments are working, I'll try and figure it out tomorrow. Above is supposed to be the picture of the warm up regulator, I have no idea where I am supposed to connect that vacuum line port to.

I am new to the air cooled Porsche world, my last Porsche was a 996 so please forgive me with the stupid questions below.

What is a decel valve and what does it do?

What is a thermovalve and what does it do?

[T77911S]

can you post the part number on the WUR

[boyt911sc]

Originally Posted by DienstXIV

Hi Tony,

I don't think the attachments are working, I'll try and figure it out tomorrow. Above is supposed to be the picture of the warm up regulator, I have no idea where I am supposed to connect that vacuum line port to.

I am new to the air cooled Porsche world, my last Porsche was a 996 so please forgive me with the stupid questions below.

What is a decel valve and what does it do?

What is a thermovalve and what does it do?

Tony

[DienstXIV]

The serial number stamped on my Warm Up Regulator is: 0 438 140 009.

the 009 is depressed instead of raise like all the other numbers and looks like it was added later since the font is different.

[SkiVT]

Good functionality description of the two in the text below the top diagram. This is from the Jim Wiliams site

[DienstXIV]

Originally Posted by SkiVT

Good functionality description of the two in the text below the top diagram. This is from the Jim Wiliams site

@SkiVT, my Warm Up Regulator only has one vacuum port and no thermo valve so should I connect my Warm Up Regulator line into one of the vacuum control lines? if so which one?

Does the Jim Williams site have a vacuum diagram for the 1975 CIS?

@SkiVT, I was born and raised in Stowe VT so I have skied most of the mountains in northern Vermont. I live in Chattanooga TN now.

[E Sully]

There is not a vacuum diagram specific to the 1975 on his site.
Here is Jim's site.
911 CIS Primer - Index

[James Brown]

remember, vacuum leaks always increase rpm on CIS systems. also, there are several vacuum ports that are plugged closed and over time the plugs can rot out and cause a leak. if you have a smoke machine leak finder, that would help.

[SkiVT]

Does the wur match this? Assuming its a vacuum assist wur, looks like the only port is on top. So the vacuum line would attach on top and follow the blue line path from the diagram. With no thermo, skip straight to decel. Adding a thermo would then match the diagram and likely help with could starts as Tony mentioned.




Grew up in Middlebury and skied/raced at virtually all the VT mountains. Know Stowe well but have never traveled to TN. We are all locked down now so no spring skiing....

[DienstXIV]

Originally Posted by SkiVT

Does the wur match this? Assuming its a vacuum assist wur, looks like the only port is on top. So the vacuum line would attach on top and follow the blue line path from the diagram. With no thermo, skip straight to decel. Adding a thermo would then match the diagram and likely help with could starts as Tony mentioned.




Grew up in Middlebury and skied/raced at virtually all the VT mountains. Know Stowe well but have never traveled to TN. We are all locked down now so no spring skiing....

That WUR is the same one that I have! the top of the decel valve has a much smaller vacuum line than the WUR so I think I need to put a T fitting in the bottom of the decel valve and hook the WUR up to that. From boyt911sc's pictures it looks like there is a T fitting on the bottom of the decel valve that might go to the WUR. The bottom of the decel valve has new tubing compared to all the other vacuum lines so someone definitely messed with the set up. I want to get everything back to how it should be first before I mess with anything.

@SkiVT, I grew up ski racing as well, made it to state one year and then chose hockey over racing. There is skiing in TN but it sucks. My dad tried going skiing a few weeks ago in Stowe but they are all shut down too...

[SkiVT]

See if these help. Unlikely its your year but still may help. I recall seeing a reducer that brings the hose size from whats needed to work on top of the wur to the smaller size of the hose to the decel. I dont have a picture or a part number for the reducer.

[E Sully]

Original part, but no longer available. 930 110 273 02 Reducing Socket

[boyt911sc]

Originally Posted by SkiVT

Does the wur match this? Assuming its a vacuum assist wur, looks like the only port is on top. So the vacuum line would attach on top and follow the blue line path from the diagram. With no thermo, skip straight to decel. Adding a thermo would then match the diagram and likely help with could starts as Tony mentioned.




Grew up in Middlebury and skied/raced at virtually all the VT mountains. Know Stowe well but have never traveled to TN. We are all locked down now so no spring skiing....

SkiVT,

Where did you get the picture? I have this WUR in my inventory. My record shows you got a different WUR from me.

Tony

[DienstXIV]

Originally Posted by SkiVT

See if these help. Unlikely its your year but still may help. I recall seeing a reducer that brings the hose size from whats needed to work on top of the wur to the smaller size of the hose to the decel. I dont have a picture or a part number for the reducer.

So it looks like some people connect the WUR to the top of the decel valve and the bottom of the decel valve, is there any difference? Both lines go to the same area under the throttle body on the intake manifold. What does the decel valve do?

On another note, my distributor vacuum line is on the front of my intake manifold, not the back and I am not sure my intake manifold has as many ports on the back of it as in the pictures but I will try and take a look today.

Thanks for the pictures SkiVT!

[SkiVT]

Hi Tony

I clipped the 009 wur picture from a post you made in a different thread from 2009!!! You are correct, I have a 089 wur you refreshed (also an FD). It is working great.

I have no real knowledge of 75 cis but hoped some of these pictures would help DienstXIV sort the vacuum hoses out.

[SkiVT]

Using a T off the top I believe allows vacuum at all times (assuming no thermo) based on whats happening in the throttle body. A picture in another thread had the vacuum hose off the bottom of the decel going to a cruise control device. I dont have one of those so am not familiar with how it works or why the bottom of the decel is a good path. Seems simple to stick with the top of the decel but maybe others with a 75 can clarify.