'77 CIS Throttle Body Vac Line Questions

[rwest]

Hello,

I'm in the process of a pretty complete refurb. of my CIS to address suspected vacuum leaks, including a many times over blown airbox. Looking at PET and another diagram, I can't figure out if the "T" that has an end capped is supposed to go anywhere, or if I can eliminate the "T" when I put a new line on to remove another connection and possible leak point?

Second question, are the two lines that have screws in them correct as well and is there a better way to seal them?

Thanks.

[T77911S]

read my posts

there is a post that shows that T on the bottom of the DV going to the WUR. you can try that.
i dont think there would be a difference between that and using one off the throttle body.
mine came off the T on TOP of the DV that came from the throttle body.

2.7 CIS WUR and Dizzy vacuum lines routing.

[rwest]

Thanks for the reply, reading the other thread, still leaves me a bit confused. My hoses seem to follow the PET, but Grady's post seems to infer that the factory diagram isn't correct, but the picture of the throttle body doesn't make it clear where any hoses originate from.

[T77911S]

gunters is wrong and henry's is wrong.
look at the pic i posted.
the 2 hoses you have plugged went to the EGR.
the smller hose in your pic that comes off on the right and disappears goes to the top of the DV AND to the TTV (or WUR if you dont have one),
if you do that then you can remove the T from the bottom of the DV and just run that hose directly to the DV.
the dist. vacuum hose go directly to the TB

[rwest]

Sorry for so many questions, I'm more visual on this sort of thing. I found this '78 diagram on Jim's site, would it be the same for '77?

911 CIS Primer - Vacuum Lines

[boyt911sc]

Originally Posted by rwest

Thanks for the reply, reading the other thread, still leaves me a bit confused. My hoses seem to follow the PET, but Grady's post seems to infer that the factory diagram isn't correct, but the picture of the throttle body doesn't make it clear where any hoses originate from.

With due respect to Grady, the diagram he attached to post #2 in the other thread is incorrect. His mechanic made the sketch not Grady. Rest in peace, we love you.

Tony

[T77911S]

that one looks fine except the dist vac. you have 2 ports on your dist.

if you read just the posts that "I" i did it will tell you all you need to know about the 77 vacuum routing.

[rwest]

T77911S,

Thanks for all your help, I think I have it mostly arraigned in my brain now!

Is the atmospheric line that goes to the top port in front of the TB for the WUR on the top or lower side of the WUR?

I'm pretty sure that I just have one vac port on my distributor though.

I'll try to get back to work on it this weekend and see if I have anymore questions.

Thanks,
Rutager

[boyt911sc]

Originally Posted by rwest

Sorry for so many questions, I'm more visual on this sort of thing. I found this '78 diagram on Jim's site, would it be the same for '77?

911 CIS Primer - Vacuum Lines

Rwest,

The vacuum diagram for the '78-'79 SC will work for your '77 except for the WUR connections. The '78-'79 WUR's are using a different WUR configuration than yours (WUR-033). Place the blue vacuum line on top and the orange line on the side port (diagram) for your WUR unless you are using a WUR-045/089 which I doubt.

BTW, the vacuum connections on your DV(decel valve) shown in the picture you posted is all connected in the wrong spots. The T-connection should be at the top and not at the bottom of the DV. People plugged and disconnected the connection because of ignorance and not knowing how the decel valve works.

First of all, test your decel valve and find out if it good or bad. If the diaphragm is not leaking and could hold vacuum, it is usable. Adjust the valve to open between 15 - 22 in. vacuum. Do you have a TV (Thermotime valve)? Keep us posted.

Tony

[rwest]

Hi Tony,

Just looked at my WUR connections and they appear correct with the top going to my thermal valve. I found the method to test the thermal valve in the factory manual and will test that along with the Decel valve.

On the Decel valve, where should I pull a vacuum and what should I do with the other ports- plug or leave open?

One issue that has always been present in my car(owned over twenty years,) is that it has very flat throttle response from idle to 2,500, then it accelerates like you would expect- no bucking or stumbling, just lackluster pickup.

Thanks,
Rutager

[T77911S]

you can remove the DV if you do not like it. if you remove it just run the vacuum line directly to the TTV. (or WUR if you remove the TTVV).

its been a while for me an a 77 but i think the WUR goes to the rear. llook at that pic i posted with the DV in it with the T on top of the DV. the WUR should go to the T on the DV then to the port in that pic, unless you remove the DV.

the flat spot could be several things. 2 i would start with: timing/advance and since you are having vacuum line issues i would check the port the WUR goes to. it needs to be connected to a port that is BELOW the throttle plate.

[rwest]

Just tested the TTV; it opened earlier than than the book spec, but it is rather warm out today- it closed after cooling down, so I'm happy that it is okay.

I couldn't find a test for the Decel Valve out of car- I have a vacuum pump. Can anyone walk me through it?

Thanks

[rwest]

Hi,

I just discovered that my cruise control is missing a vacuum line. Could the capped off "t" at the bottom of the decel valve be where the line should run to?

Thanks

[rwest]

Anyone have an idea where the cruise control vacuum line connects to the engine? Could it be the blue capped connection on the bottom of my decel. valve?

Thanks,
Rutager

[boyt911sc]

Originally Posted by rwest

Just tested the TTV; it opened earlier than than the book spec, but it is rather warm out today- it closed after cooling down, so I'm happy that it is okay.

I couldn't find a test for the Decel Valve out of car- I have a vacuum pump. Can anyone walk me through it?

Thanks

Rwest,

From a cold start, how long it took the TTV to open? 10 sec.? 20 sec.? Thanks.

Tony

[rwest]

Tony,

I didn't actually time it, but it was maybe around 10 to 15 seconds on an 80 degree day.

I also tested the aux. air regulator and it slowly closed when power was applied.

I really have no reason to believe any of my components are bad as the car ran pretty well before. I knew my air box was cracked and mixture was rich, so I decided to do a renew on the CIS to get rid of any possible air leaks and get it running as well as possible. I'm replacing all the vacuum lines, seals, gaskets and the injector lines as well.

Last question, would it be okay to hook up the cruise control to the port that is capped off with the blue cap on the throttle body in the first picture?

Thanks for all your help.
Rutager

[T77911S]

Originally Posted by rwest

Anyone have an idea where the cruise control vacuum line connects to the engine? Could it be the blue capped connection on the bottom of my decel. valve?

Thanks,
Rutager

probably. it needs manifold vacuum