Decel Valve Vacuum Lines?

[Wew]

Making progress working around the car and now I am back to the decel figuring out vacuum problems. I don't have to look very far.
I have two vacuum lines that are open and when I put my thumb over the open end of the line there is substantial vacuum and the idle on the car drops significanlty and idles roughly. Current idle is to high at around 1200-1400.
I have attached a pick I stole from another pelicaner along with my original image in this thread. The Vacuum line with the arrow goes towards the drivers side of the car and is laying in the engine bay open. I cannot fine a home for this line Any ideas are much appreciated. EGR and WUR have vacuum lines intact along with distributor and from the bottom of the smog pump as well.
My targa 1978 is a California car so it has all the smog that was required for it's time of manufacture.
I have searched high and low and still can't figure out where this line goes...

Any help, super much appreciated. Already looked into above suggestions.

Second is an old vacuum line coming out of the center area next to the clutch cable. A tiny little vacuum line, I believe is attached to the brake system somehow. As it works its way up and toward the wall to venture into the engine compartment it was broken and taped out of the way to prevent it from falling and tangling into other stuff...
Again in the engine compartment I can't find the other half of the line and ultimately where it is supposed to connect.

All help and information is much appreciated.

Thanks again,

Gary

[Vereeken]

Attached is the vacuum diagram I drew based on experience. If you have a 78 you should have a CIS with no 02 sensor. But I could be wrong as i am not into US specs.

In any case the decel valve is generic. At least this type.

You also need to verify the type of WUR.

As to the second small diameter tube that is plugged and runs into the firewall. this is for me one of life litlle mysteries.
I have seen the same approach on half a dozen cars and I too made the assumption that it should go to the brake booster but I do not see the point.

I have always thought that it would have gone to the air pump and that most owners got rid of that airpump but I have never had any confirmation.

The way in which your decel valve is T-d off is not correct according to me. It should T off at the top in the small diameter section tube.

[Jim Williams]

Check here:

Vacuum line connections

[timmy2]

Looks like someone teed off the line for cruise control maybe? The bottom of my decel valve has no tee connector and just goes straight back to the throttle body.

[Wew]

Thanks for the input Gents, I took the 1978 CIS Vacuum diagram which includes the EGR for California smog. My Targa was originally built for California and still has all the smog attachments.
I hi-lighted the normal lines in blue and then the bottom one in orange that lays open in the engine compartment. And like a said, it's got a boat load of vacuum and when I put my thumb over it idle drops dramatically and car sputters and eventually dies.

I am wondering what purpose this line serves if any? Maybe helps it to decelerate quicker?

Can I just go ahead and eliminate the line and close the system?

When I do, I would imagine I need to re time the car and then move into fuel mixture and idle if necessary...?

Am I on the right path?

Thanks,

Gary

[Vereeken]

I would do exactly that. I have never seen that "orange" vacuum line.

You say you have all smog equipment still intact. Can you share a picture of # 8 with us?

Kr

Michel

[Wew]

Will take some photo's this evening and post when I finish up my day in the salt mines.

[T77911S]

the red one is not suppose to be there.....unless it was for a cruise....if it even had one or if that is where it would get its vacuum from.

[Jim Williams]

What that shows is that you have a significant vacuum leak into your air box. At the least it needs plugging up. It's not a factory connection. Some one must have had something "kludged" in which is not longer evident.

Your mixture is probably leaner than it should be.

[Vereeken]

What if that orange tube is someone's solution for a stuck Idle screw.

Realizing he could not adjust his idle anymore he introduced a new air source in order to get the revs up...

Ha, the things we see...

In any case we all agree that it should not be there.

[Wew]

Michel,
I think this is what you are looking for. Sits below the smog pump for the ca porsche.

Hope this is correct. And there is a vacuum line that comes off of that.

I checked the cruise control unit and it does have a vacuum line attached and it is way bigger than the one coming off the decel.
Looks like I am going to plug it and watch my idol drop.
Anyone know of any great posts to wak me through dialing her back in properly is much appreciated.
Thanks,

Gary

[Vereeken]

Thanks Gary, indeed what I was looking for. Never ever seen one. I have the impression everyone removed them. AS far as I understand they where pretty hopeless.

You say that there is a VAC line coming from it. Where does it run too?

Thx

Michel

[Wew]

Beats the heck out of me Somewhere on the throttle body I believe.

[Vereeken]

It must come from the throttle body.

But if it comes from the front of the TB (next to the air intake) and it is the lowest of the 2 it would confirm my theory that all these vacuum connections where plugged at the time they removed the air pump and it would solve one of my remaining questions re vacuum connections on the SC.