1981 GSL (seemingly) stock. Starts but idles high. New fuel lines, pump & filters. Vacuum leak somewhere due to high idle and no brakes.

I tried to search for a similar thread but was not successful.

As I was inspecting my high RPM issue (3000 rpm) and looking for my big vacuum leak I looked up the vacuum diagram.


And compared it to my rats nest because I saw that my leftmost (Leading vacuum..) was capped of.




Then it hit me that I just have 5 Valves, not 6 like everyother nest I have seen online.




Picture I took before replacing lines, plugs, wires.


Questions:
- why is my leading vacuum valve capped of?
- why is my Trailing Vacuum valve missing?
- did someone mess with it or is this some kind of "variation"
- how do I fix this?

 

Your car has not been modified. That's how the 81 RX-7 emissions rack was set up. Here is a picture from a book I have showing the 81's updated emissions rack. It appears to be the same as yours.

 

+1 not every year has solenoids for both, and you can see that there isn't a spot on the vacuum rack for another solenoid. i have seen some that did have the extra space for that solenoid, and then i think 84-85's have it

 

Just adding to the info, some models came with as few as three and as many as seven (if I recall correctly). It depends on the year and whether it was a Cali car or not. There were quite a few revisions to the vacuum rack over the years. My SA had four for example.

As for the POs questions, on your vacuum rack the leading and trailing advance share the same vacuum source. If you look at the lines going to the dizzy you can see they join at a tee on the vacuum rack. As for whether they're supposed to be capped off or not I can't say. I will however mention that them being capped off will not inherently cause any issues, and at worst a vacuum leak if the caps are failing.

Not having vacuum advance will result in slightly worse mileage and throttle response, but it's a minimal difference and would not impact the vehicles ability to operate.

 

FYI - when you quote people's posts, it makes scrolling unnecessarily difficult. Unless you're asking for clarification on a specific point, quoting text tends to clutter up the board.

Also, on the 84/85 GSL-SE, ﹰthere are even fewer Vent and Vacuum Solenoid there, as the Fuel injection doesn't need a lot of air control to operate smoothly. Good luck,