Ok, sold my '87 GXL to a fellow racer, he's replaced the motor, but there are 3 nipples for vacuum lines on the bottom of the intake, can't figure out where they go to. I'm useless on this, figured I'd ask you guys. Any help? Thanks!

 

ill take a look on my fc tomorrow and take some pics if i can so you can see where they go

 

Thanks!

 

Any luck? Anyone?

 

Does not look RX7 to me at all. Much less a 87 non turbo. Just my opinion.

 

Ok so your in luck because its a real easy fix, the right and left tubes can be blocked off, im saying this because that part of my car hasd never been modified and mine are blocked off, so my suggestion would be to do that, and for the middle tube, it goes up to this white piece ( only white piece in the picture) and on that same white piece there is a second tube that leads to a green piece, sorry for using the word "piece" so much im still learning. But this information should be everything you need to fix the problem you addressed, hope i helped!

 

in your picture the "piece that the middle tube plugs into is yellow-ish, its directlly above the middle tube inlet

 

it looks extremelly like an 87 non turbo

 

Thanks!

 

Ok so I don't remember where all of them go but I can help with at least one. On the throttle body directly above these nipples is the (yellowish in your pic) plastic piece with two nipples on it. It helps to control warm up idle and the two secondary (choke) butterflys. Connect a vacuum hose from one of the three nipples on the intake runner up to one of the nipples on the plastic vacuum switch (which is controlled by coolant temp that runs thru it) then take another hose with the green and black one way valve and connect it to the vacuum motor on the front of the throttle body. Its right on the front next to the intake elbow, it has one nipple on it for vacuum and then the arm connects to the secondary (choke or cold start) butterflys that block off the secondary intake butterflys when the engine is cold.

I hope that made sense, I'm sorry I can't take pics or tell you where the other two nipples go but I no longer have an s4 motor to check it on.

 

Yeah, I was wrong.

One goes to the plastic outfit called a water thermovalve (see non tubo FSM, please). The water thermovalve controls the double throttle diaphram on the fwd side of the throttle body. Double throttle diaphram closes the outer set of secondary throttle plates when the engine is COLD. Those plates are spring loaded to open is the double throttle diaphram fails (all I've seen are in the failure mode i.e. the diaphram inside is shot).

Water thermovalve is plastic and has two vacuum nipples. One goes to one of the nipples in your picture and the other thermovalve nipple gets a vac hose and the other end gets attached to the nipple on the double throttle diaphram.

One came capped on my used cars. The other can go to the cruise control motor (vacuum operated on a series four non turbo).

 

Hi everyone,
I am rebuilding a throttle body for my third engine replacement, figured I should learn how this system worked!

The #2 secondary throttle valves are operated by a diaphragm that is controlled by the vacuum from the secondary intake manifold. The primary and secondary manifold are completely separated.

The spring in the diaphragm will keep the throttle plates completely open when there is no vacuum applied,

Upon a cold start, the thermo valve will allow vacuum to be applied to the diaphragm causing it to almost close at 10in of vacuum.

This is to prevent a lean air/fuel mixture from occurring (hesitation) when the secondary throttle plates are opened.

When the coolant temperature reaches 140 degrees F. the vacuum is blocked by the thermo valve, and the #2 secondary valves are completely open.

In line with this is a DELAY valve (not to be confused with a check valve which is a one way valve) that slows the opening of the #2 throttle valves.

So, the net effect of this system is to prevent the engine from bogging down when you try accelerating while the engine is warming up. Think trying to get up the speed to merge onto the freeway before the engine is fully warmed up! You will feel a lack of acceleration under these conditions, but you won't experience any hesitation!

Once the thermo valve get to 140 degrees F. the vacuum is blocked off and the spring in the diaphragm will hold the #2 secondary throttle plates fully open. This ends the purpose of this system while the engine is up to operating temperature.

 

good info, but 13 years too late lol

 

I don't pay any attention to the date of the last post!

My replies are for everyone that has these issues today!


Vacuum lines and piping

 

spider

series 4