UKKid35

There are two vacuum lines clearly shown on the top of the throttle body (going to "F" - Vacuum Valve and to the 5 Way connector), but there are also two underneath, one appears to go to "I" - Secondary Air Valve, but where does the other go? I can't see it in the WSM illustration:

GoRideSno

UKKid35,
You did not mention the line that goes to the flappy valve. Could it be this?
Andy K

UKKid35

Afraid not, L - Flappy, K - Flappy Solenoid, d - from Vacuum Resevoir

I'll try to post a pic of the manifold and throttle body later today so you can see the vacuum line in question (it's off the car and was not connected when I removed it)

Tony

FYI..on my last car there were 2 vacuum connections underneath also. one was sealded up for some reason and not used?


I try and dig up a pic...that wil be going back a while.

UKKid35

Tony

yup..just like that but one was bent over and crimped closed.

ErnestSw

By your description I think you have your orientation upside down. The two connections you show in your picture are going to end up on the BOTTOM of your throttle body when you install it in your car. The red one will go to the 5 way connector and the other will go to F.
The one for the flappy (coming off of L, which will be on top of the throttle body under the intake) goes to K on the left front of your engine, and the last line goes from B to I.

shaaark89

paul,
i've seen this before too, and interestingly, my 89 (intake off now) only has one port on the bottom of the tb.
in other ealier s4's i've seen two with one blocked off. never seen them both used. the one from under there should go to I which is an air valve for the smog pump. should exit under the rear of the intake around the passenger (us) side to the airpump.

UKKid35

Thanks guys, I've not seen any illustrations or photos where there are two ports which is why I posted the pic - so you'd believe me! Because I've just removed the airpump I should be able to cap both ports now.

Hilton

The pic that's missing from Paul's post above is this one:

blazing928

I think the spare one would go to the air pump valve. It gets capped when the air pump is removed
.....or the valve that releases the fuel cannister gasses, thats the long one, comes out the RH side of the inlet manifold, takes the long way there!

Tails

The question that you ask is fully explained in a previous thread titled "High Idle Speed Suggestion" by stevedavis from UK. If you type in High Idle into the 'search' facility it will bring up lots of threads and you will find the above thread, which fully explains the vacuum connections on MY from 1987 and also the different connections for cars for various countries.

Interesting thread that should help you.

Tails 1990 928S4 Auto

Tails

The question that you ask is fully explained in a previous thread titled "High Idle Speed Suggestion" by stevedavis from UK. If you type in High Idle into the 'search' facility it will bring up lots of threads and you will find the above thread, which fully explains the vacuum connections on MY from 1987 and also the different connections for cars for various countries.

Interesting thread that should help you.

Tails 1990 928S4 Auto

Tails

The question that you ask is fully explained in a previous thread titled "High Idle Speed Suggestion" by stevedavis from UK. If you type in High Idle into the 'search' facility it will bring up lots of threads and you will find the above thread, which fully explains the vacuum connections on MY from 1987 and also the different connections for cars for various countries.

Interesting thread that should help you.

Tails 1990 928S4 Auto

John Speake

These two ports under the plenum are described in a picture in the Tech Info for MY87. The second of the two ports under the plenum is described as "4) Blowoff switching valve California".

The two ports on top are labelled 1) Tank venting valve 2) Pressure regulator/Pressure damper

The other port under is shown a 3) Blowoff switching-over valve 49 States and M298/M299

Hope this helps.