Vacuum line routing pics and brake booster line (Page 1/3)
Filben APR 05, 06:16 PM
I am trying to piece together this puzzle. 86, 4 speed, 3.4 swap, the car was half disassembled when I bought it, I can not figure out where all the vacuum lines go. Theres a rubber hose line off the EGR solenoid, where does that go? Do I need all the purge hose lines to the emissions canister(can I just delete this stupid thing)? Theres a hard vacuum line along the firewall, where does that go? I am not doing the cruise control right now but where does that pick up vacuum from? Any pics of actual vacuum routing and not grainy pics of schematics would be greatly appreciated. Also, where does the brake booster get vacuum from?

[This message has been edited by Filben (edited 04-05-2025).]

cartercarbaficionado APR 05, 06:26 PM

quote
Originally posted by Filben:

I am trying to piece together this puzzle. 86, 4 speed, 3.4 swap, the car was half disassembled when I bought it, I can not figure out where all the vacuum lines go. Theres a rubber hose line off the EGR solenoid, where does that go? Do I need all the purge hose lines to the emissions canister(can I just delete this stupid thing)? Theres a hard vacuum line along the firewall, where does that go? I am not doing the cruise control right now but where does that pick up vacuum from? Any pics of actual vacuum routing and not grainy pics of schematics would be greatly appreciated. Also, where does the brake booster get vacuum from?



everything goes exactly the sane as a stock 2.8l v6 luckily.
i have the charcoal canister missing on my v6 fiero and my solution was to just make a purge vent so i didnt have an open hose into the fuel tank or filling the engine bay with fumes
the line on the front firewall is for egr stuff thst is no longer used (plug the vent in the air filter can since the fiero goes through the center out)
im not sure about cruise as im actually missing mine
Filben APR 05, 06:52 PM
And where do these lines circled in red go?


Also what goes to this port in yellow?
cartercarbaficionado APR 05, 06:58 PM

quote
Originally posted by Filben:

And where do these lines circled in red go?


Also what goes to this port in yellow?


the big port is the egr tube thats now unused. the small tube coming off of the air intake tube is for something but its not there anymore on my v6 stuff.
the yellow? no idea becuase its not on my v6 stuff unless its coming from the rear valve cover. is it coolant perhaps?
edit: wait i might be an idiot. get a betrer picture please so i can see if im a moron

[This message has been edited by cartercarbaficionado (edited 04-05-2025).]

Filben APR 05, 07:22 PM

quote
Originally posted by cartercarbaficionado:

the big port is the egr tube thats now unused. the small tube coming off of the air intake tube is for something but its not there anymore on my v6 stuff.
the yellow? no idea becuase its not on my v6 stuff unless its coming from the rear valve cover. is it coolant perhaps?
edit: wait i might be an idiot. get a betrer picture please so i can see if im a moron




The yellow is some big metal tube to the back of the throttle body. I have piles of random parts in the garage and that is where that one went I suppose. I have the MAP to fuel pressure regulator. I found the port for the brake booster(its the big one on the back of the intake manifold I think, it was NOT hooked up there when I got the car). I have the PCV valve hooked up. Right now I need the EGR control valve thingy, it has THREE lines from it, two from one end, and one hose from the other.
Filben APR 05, 07:28 PM



I have no idea where these go. Orange, blue, and green. GM vacuum spaghetti is fun.
cartercarbaficionado APR 05, 07:31 PM

quote
Originally posted by Filben:


The yellow is some big metal tube to the back of the throttle body. I have piles of random parts in the garage and that is where that one went I suppose. I have the MAP to fuel pressure regulator. I found the port for the brake booster(its the big one on the back of the intake manifold I think, it was NOT hooked up there when I got the car). I have the PCV valve hooked up. Right now I need the EGR control valve thingy, it has THREE lines from it, two from one end, and one hose from the other.


seems like you got it figured out then.
the one end thats smooth on the egr controller can just be left open. the 2 small lines are the important ones. i think my 87 gt had that line litterally plugged onto a stud when i got it
1985 Fiero GT APR 05, 07:33 PM
The yellow is the line for the idle air control, it is vital to be hooked up, if it is open, engine will have no idle control and a half inch open vacuum port (it'll rev real high).

Large metal line is the pre recall PCV vent routing (not EGR!), the small rubber hose is connected to a small diameter metal line on the firewall that leads to a rubber hose to the EGR solenoid. The large metal line is unused, the rubber hose should be hooked up, but isn't as vital as the iac line.
1985 Fiero GT APR 05, 07:37 PM

quote
Originally posted by Filben:


The yellow is some big metal tube to the back of the throttle body. I have piles of random parts in the garage and that is where that one went I suppose. I have the MAP to fuel pressure regulator. I found the port for the brake booster(its the big one on the back of the intake manifold I think, it was NOT hooked up there when I got the car). I have the PCV valve hooked up. Right now I need the EGR control valve thingy, it has THREE lines from it, two from one end, and one hose from the other.



Brake booster is the big one on the passenger side of the intake, the rear valve cover PCV valve goes to the large port on the bottom of the intake, the front valve cover PCV goes through a metal tube to the rubber intake just before the throttle body.

The EGR solenoid (black thingy) one line goes to the throttle body switched vacuum (one of the 2 small vacuum connections on the bottom of throttle body), one to the EGR valve (on the exhaust y pipe) and the larger one by itself goes to the small diameter firewall metal tube going to the rubber tube beneath the air filter.
Filben APR 05, 07:39 PM

quote
Originally posted by 1985 Fiero GT:

The yellow is the line for the idle air control, it is vital to be hooked up, if it is open, engine will have no idle control and a half inch open vacuum port (it'll rev real high).

Large metal line is the pre recall PCV vent routing (not EGR!), the small rubber hose is connected to a small diameter metal line on the firewall that leads to a rubber hose to the EGR solenoid. The large metal line is unused, the rubber hose should be hooked up, but isn't as vital as the iac line.




Okay, green is hooked up(I found a pipe laying in the parts pile and the hole in the back of the throttle body that matched). Now in the new pic I uploaded, GREEN goes to the small metal line along the firewall and then at the other end I hook that to the EGR valve ?