Unknown hose

[gerben1986]

Hi,

This evening I checked the vacuum lines of my 1980 911 SC.
And I found this hose, the strangest thing is that it is closed with a screw.


I starts at the throttle body and has around 5 of 6" of hose on it.

Does anyone knows where this belongs to or how this should be attached or where it should be attached to?
Unfortunally I also can't find it in the PET...


Sorry for the crappy pic... When it is not clear enough I'll make one with a normal camera.

[The cap'n]

You don't say where you are, but cars destined for the US have vacuum diagram stickers inside the engine lid. That tells you where all the vacuum lines attach. If you don't have such a label, you'll need to find a diagram or another car to look at.

The Cap'n

[Robey5]

That is a vacuum hose that - on the 1979 I am working on - connects to the cruise control. (this is located on the driver's side, near the fire wall, and the vacuum line connects immediately adjacent to the fire wall).

However, on my friend's 1980 - there is a line that goes to the distributor (2-pod vacuum advance and retard). This line may go to any one of these 3 places. Based on the idea that people want to try to keep the timing advanced a bit at all times, this may be the retard line that is plugged with a screw (you can thank your PO).

[gerben1986]

Sorry, I'm in the Netherlands. It is a EU car, without cruise control.

Accoring to the response of Robey I should check if there is an empty connection on the distributor. If that's the case this one should originally be connected to that one?

And for as far as I can see it shouldn't be a problem?

Because the real 'problem' I have is that the acceleration of the car isn't that good.
It isn't very agrassive between 3,000 and 4,000 rpm. But once that's over it pulls as hard as you expect of a Porsche...

[Robey5]

Snap a picture of the "engine room." Focus on the distributor, and the connections that may exist there.

I am working on a 79 911SC - US non-California, and my friend's is a 80 911 SC US.

Since I too do not have the stickers that the Cap'n is referring to, there are vacuum lines that were a mystery to me when I was putting the 79 back together.

A picture will really help.

[Josh D]

Verify what engine type you have. An '80 RoW would be a 930/09. 930/09 had plastic fuel lines, not metal like in the pic.

[boyt911sc]

Gerben,

Do you mind posting the FD # shown in the picture you posted? Just need the last three (3) digits. It should look like 0-438-100-xxx. Thanks.

Tony

[gerben1986]

I'll take the picture of the engine tomorrow and also check the engine code. Because it is a SC with the 3.0L I expect it is 930/09, but will check it tomorrow.

[gerben1986]

I check this afternoon, and I found a really strange/interesting thing.

It seems to be a 930/03. That means that the engine is from 1978, and had 180HP instead of 188HP.

I know that there was a rebuild engine in the car (seen the invoices and the engine is very clean at the bottom). But I expected they put in the same as the one which came out of the car...

Picture of the distributor:



Picture of the engine bay:


Where should this hose belong to?
And can it be the reason for the bad acceleration performance?

[Josh D]

Interesting.

A 930/03 wouldn't have metal fuel lines either, but it's possible the plastic ones were swapped for metal ones at some point.

I recommend getting the CIS numbers for Tony so he can decipher what year CIS system you have.

[gerben1986]

What would be the biggest impact of the change from plastic to metal fuel lines?

And according to Robey5 I expected that the vacuum line should go to the distrubutor, but there is no connection for it...

The # of the fuel distributor is: 0 438 100 097
The # on the distributor is: 0 237 301 009

[gerben1986]

Based on this thread: Could anyone tell me where this vacuum hose goes? 78 SC
and this website: 911 CIS Primer - Vacuum Lines

I developed this idea:
I have a throttle body of a '80 SC, with support for an extra vacuumline for the distributor.
I have an '78 engine and a '78 distributor. On this distributor there is only place for one vacuumline, not for the second.

So, that is why the put a screw in it.

Is this logical? In the PET I see 2 numbers for the throttle body:
930 110 248 01
and
930 110 248 02
What is the difference between them?

[Robey5]

Your theory may be correct. (Speculating) This set up looks like someone put a newer set of metal fuel lines - and maybe a whole newer CIS system on the 'older' engine. I am not thinking that your running issue is because only of this (now plugged) vacuum line, but likely to be a few different contributors.

Tony can get you pointed in the right direction; provide the FD number to him -- he really knows CIS components and such. While you're at it, you may as well provide him the number(s) on the WUR.

[The cap'n]

Just set the ignition timing as a '78 and you should be fine.

The Cap'n

[Josh D]

Originally Posted by gerben1986

What would be the biggest impact of the change from plastic to metal fuel lines?

Nothing negative, just that it isn't stock, which could mean other parts of the fuel injection aren't original to the car, or more importantly, to the motor.

There were many varitions of the SC 3.0 between RoW and US spec in it's 6 years. You can't just swap certain parts from one spec 3.0 to another. Examples of this would be the WUR or the fuel distributer. The fuel lines are no big deal, but are not original to MY '80 or the 930/03 that is in your car. That means other things could be different as well. First thing to do is to figure out exactly what you have. There are members here, like Tony, who know CIS very well and understand, better than I, what components of various years are compatable.

[gerben1986]

Where can I find the # of the TB while it is still in the car?

Tony: do you know the difference between these 2 TB's?:
930 110 248 01
and
930 110 248 02
I expect that the 01 has an extra connection for a vacuumline.

And I'll try to make a short movie about the accelerating problem today.