Could anyone tell me where this vacuum hose goes? 78 SC

[Eric D.]

I'm geting ready to put this engine back in and have no clue where this vacuum line goes. I bought the car already apart otherwise I would have marked it. It's a long hose . I have one for the vacuum advance already Any idea?
Thanks, Eric

[allaircooled]

Just a guess, but maybe brake booster?

[Gogar]

+1 (guessing) brake booster.

[mreid]

That looks too small for the brake booster. However, I don't have a better guess.

[pete3799]

Not sure where it goes but I believe this (blue arrow) is your booster hose.

[timmy2]

Vacuum pod for the distributor.
California car has an EGR controller on it as well.
Take a good look at this:

911 CIS Primer - Vacuum Lines

[pors1968]

Might be canister line

[Flat6pac]

The line is above the butterfly. Pulls the vacuum advance of the distributor as the high RPM require more advance.
The power brakes comes off the side of the airbox and is a larger hose 12mm.
Bruce

[gamin]

As usual Bruce nails it!

[Eric D.]

I'm thinking it could be for the air injection. But now I'm not sure if I got them mixed up. In this first picture the red arrow is pointing to the port/ hose that is going to the vacumm advance. Is this right or should I use the other port?
As said above it looks like it's above the throttle plate so it should be ok there? Then I'll just cap the other port.






Air injection part not being used.


Thanks every one for the replys, Eric

[timmy2]

Originally Posted by timmy2

Vacuum pod for the distributor.
California car has an EGR controller on it as well.
Take a good look at this:

911 CIS Primer - Vacuum Lines

Really..... The diagram Jim has posted on his website is correct!
As Bruce stated like I did earlier, the line you are asking about is for your distributor. Take a good look at the drawing, you will figure out where all the lines go.
Hint: the yellow one from the WUR goes to the opposite side of the TB on the rear bumper side of the car. (dotted lines)

[boyt911sc]

Originally Posted by pete3799

Not sure where it goes but I believe this (blue arrow) is your booster hose.

Dennis,

I don't think the engine is using an EGR based from the picture attached. The EGR uses both connections and one (1) port it is plugged (see picture above). Below is the EGR with hoses going to the throttle body:




Plus the hose in question is too long to be used for the EGR or distributor. If I have to guess, it might be coming from the carbon canister like someone earlier mentioned or to the smog pump (?). I have removed my smog pump and has not seen an SC engine in a while with a smog pump in place.

Tony

[allaircooled]

It couldn't be from the carbon canister, that would be a source of unmetered air correct?

[boyt911sc]

Originally Posted by allaircooled

It couldn't be from the carbon canister, that would be a source of unmetered air correct?

Chris,

You are correct!!! This hose could not been used for the carbon canister.

Tony

[timmy2]

Just look at the drawing,. IF there is an egr then one of the 2 ports would be used for the egr and the other would go to the bottom of the egr and then to the distributor....
As the one port is plugged I would assume no egr so the line goes to the distributor vacuum canister.

[timmy2]

I guess a picture speaks 1000 words... Follow the line back from the distributor (device #6)
If no EGR, then just delete the lines to it (device #7) and it will be a direct line to the dizzy...(plug the other port)

[timmy2]

As pictured:

Smog Air pump line (8) comes from the front lower port, Top WUR line (yellow) comes from top front port.

Vacuum advance comes from rear port left, and lower WUR line (blue) via vacuum control (decel) 9, and Thermo Valve 4, comes from rear port right.

[Eric D.]

I printed that diagram last night. No EGR. But I did mix them up. My vacuum advance is at the smog air pump line. I don't think it matters though since they are both ported vacuum? (above the throttle plate)

Dennis thanks so much. Your a big help as always.