Pennock's Fiero Forum
  Technical Discussion & Questions
  Vacuum line routing pics and brake booster line

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
Vacuum line routing pics and brake booster line by Filben
Started on: 04-05-2025 06:16 PM
Replies: 20 (172 views)
Last post by: Vintage-Nut on 04-08-2025 02:03 PM
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 06:16 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
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).]

IP: Logged
PFF
System Bot
cartercarbaficionado
Member
Posts: 858
From: cusick, Washington, USA
Registered: Sep 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 06:26 PM Click Here to See the Profile for cartercarbaficionadoSend a Private Message to cartercarbaficionadoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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

IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 06:52 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
And where do these lines circled in red go?


Also what goes to this port in yellow?
IP: Logged
cartercarbaficionado
Member
Posts: 858
From: cusick, Washington, USA
Registered: Sep 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 06:58 PM Click Here to See the Profile for cartercarbaficionadoSend a Private Message to cartercarbaficionadoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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).]

IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:22 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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.
IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:28 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post

Filben

83 posts
Member since Nov 2024



I have no idea where these go. Orange, blue, and green. GM vacuum spaghetti is fun.
IP: Logged
cartercarbaficionado
Member
Posts: 858
From: cusick, Washington, USA
Registered: Sep 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:31 PM Click Here to See the Profile for cartercarbaficionadoSend a Private Message to cartercarbaficionadoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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
IP: Logged
1985 Fiero GT
Member
Posts: 958
From: New Brunswick, Canada
Registered: May 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:33 PM Click Here to See the Profile for 1985 Fiero GTSend a Private Message to 1985 Fiero GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.
IP: Logged
1985 Fiero GT
Member
Posts: 958
From: New Brunswick, Canada
Registered: May 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:37 PM Click Here to See the Profile for 1985 Fiero GTSend a Private Message to 1985 Fiero GTEdit/Delete MessageReply w/QuoteDirect Link to This Post

1985 Fiero GT

958 posts
Member since May 2023
 
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.
IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:39 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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 ?
IP: Logged
1985 Fiero GT
Member
Posts: 958
From: New Brunswick, Canada
Registered: May 2023


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 07:46 PM Click Here to See the Profile for 1985 Fiero GTSend a Private Message to 1985 Fiero GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Filben:
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 ?


No, green goes along firewall to the rubber hose you mentioned at the beginning (beneath air filter), blue and red go to throttle body and EGR valve, in that order, blue to rear most port on throttle body, red to EGR valve. The front (bottom) port on the throttle body goes to the dogbone location then across the trunk to the evap canister. The drivers side small port on the intake goes to the dogbone, across the trunk, to the cruise control and evap system.
IP: Logged
PFF
System Bot
olejoedad
Member
Posts: 19728
From: Clarendon Twp., MI
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 207
Rate this member

Report this Post04-05-2025 08:08 PM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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?




The big tube is unused, but it was for the PCV system, not the EGR.
The small hose plugged in to the small metal tube that runs with the big metal tube across the firewall, another small hose plugged into the EGR solenoid and supplied vent air.

The yellow port is connected to the tube that comes out of the lower port on throttle body that faces the upper intake. There should be a nipple and some 9/16" hose that connects to the TB tube.

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

IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 08:14 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 1985 Fiero GT:


No, green goes along firewall to the rubber hose you mentioned at the beginning (beneath air filter), blue and red go to throttle body and EGR valve, in that order, blue to rear most port on throttle body, red to EGR valve. The front (bottom) port on the throttle body goes to the dogbone location then across the trunk to the evap canister. The drivers side small port on the intake goes to the dogbone, across the trunk, to the cruise control and evap system.


Okay, I think I have it all now. I have every line laid out, every port accounted for so hopefully that does it when I stick the engine back in. Thank you everyone!
IP: Logged
olejoedad
Member
Posts: 19728
From: Clarendon Twp., MI
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 207
Rate this member

Report this Post04-05-2025 08:15 PM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post



This illustration from the FSM showsdetail of the yellow circled port plumbing.
IP: Logged
Patrick
Member
Posts: 38385
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 465
Rate this member

Report this Post04-05-2025 09:47 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by olejoedad:

The small hose plugged in to the small metal tube that runs with the big metal tube across the firewall, another small hose plugged into the EGR solenoid and supplied filtered vent air.


Joe, take a closer look to where that small tube connects to the air filter assembly. Oddly enough, it's prior to the filter.

IP: Logged
Vintage-Nut
Member
Posts: 1476
From: California
Registered: Apr 2020


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-05-2025 10:32 PM Click Here to See the Profile for Vintage-NutSend a Private Message to Vintage-NutEdit/Delete MessageReply w/QuoteDirect Link to This Post
2.8L Vacuum Lines

IP: Logged
olejoedad
Member
Posts: 19728
From: Clarendon Twp., MI
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 207
Rate this member

Report this Post04-05-2025 10:43 PM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Joe, take a closer look to where that small tube connects to the air filter assembly. Oddly enough, it's prior to the filter.


You are right, it would pull a slight vacuum on the EGR solenoid vent. But it isn't filtered, that was incorrect.

Thanks, I have edited my previous post.

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

IP: Logged
Filben
Member
Posts: 83
From: missouri
Registered: Nov 2024


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-06-2025 09:24 AM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Vintage-Nut:

2.8L Vacuum Lines


Damn, that is the best diagram I have seen so far. This should be the sticker under the rear hatch.
IP: Logged
Vintage-Nut
Member
Posts: 1476
From: California
Registered: Apr 2020


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-06-2025 12:31 PM Click Here to See the Profile for Vintage-NutSend a Private Message to Vintage-NutEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thank you and I believe it is fully complete without any missing paths...
IP: Logged
olejoedad
Member
Posts: 19728
From: Clarendon Twp., MI
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 207
Rate this member

Report this Post04-08-2025 09:39 AM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Filben:


Damn, that is the best diagram I have seen so far. This should be the sticker under the rear hatch.


Take your pick...


IP: Logged
Vintage-Nut
Member
Posts: 1476
From: California
Registered: Apr 2020


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-08-2025 02:03 PM Click Here to See the Profile for Vintage-NutSend a Private Message to Vintage-NutEdit/Delete MessageReply w/QuoteDirect Link to This Post
With some missing vacuum paths...
IP: Logged
PFF
System Bot

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock