1984 vacum lines
Thread Starter
Advanced
Joined: Oct 2002
Posts: 55
Likes: 0
From: San Antonio TX
1984 vacum lines
I searched the threads but did not find a direct answer, so I'd like to ask this one. It's not in the manuals I have, or on the diagram in the engine compartment.
On my 1984 (auto/ac), the pewter vacum port located at the rear of the intake broke off. I just plugged 'er up as all I was doing those days was autoXing the car (foot to the floor on the gas or the brake and nothing else). Nowadays, I trying to get a rough mid-throttle condition solved.
I've replaced the valve and replaced vacum lines for the TBI system according to the diagrams. The EGR and MAP sensor liness are done, the port tubes are capped for each TBI. However, on this particular line, it connects to another goofy T-style plastic fitting: one end runs to the fuel canister, one end connects to the intake manifold port (in the rear), and one small diameter line connects to......
Are there any resources you all know of, or does anyone have intimate knowledge with what I'm trying to solve?
TIA, Mike
On my 1984 (auto/ac), the pewter vacum port located at the rear of the intake broke off. I just plugged 'er up as all I was doing those days was autoXing the car (foot to the floor on the gas or the brake and nothing else). Nowadays, I trying to get a rough mid-throttle condition solved.
I've replaced the valve and replaced vacum lines for the TBI system according to the diagrams. The EGR and MAP sensor liness are done, the port tubes are capped for each TBI. However, on this particular line, it connects to another goofy T-style plastic fitting: one end runs to the fuel canister, one end connects to the intake manifold port (in the rear), and one small diameter line connects to......
Are there any resources you all know of, or does anyone have intimate knowledge with what I'm trying to solve?
TIA, Mike
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Left rear corner of the intake manifold lid, right? It is strange looking because the threads are quite large for the size hose it takes. If that is what you are referring to, I broke that same fitting on my car this spring. I got a replacement from Chevy. The nipple for the vacuum hose was larger in diameter than the old fitting, but I was able to force the hose over it. I'm 99% sure that is the vacuum source for the cruise control.
RACE ON!!!
RACE ON!!!
Thread Starter
Advanced
Joined: Oct 2002
Posts: 55
Likes: 0
From: San Antonio TX
Okey Dokey:
I located the vacum lines from the Cruise Control diaphram.
One line disappears below the booster of the Master Cylinder. I'm guessing that's okay as it didn't trickle free.
The second line ran to a standard T - one line heads off to the fuel canister, and the second line heads up toward the vacum valve I've replaced on the intake.
However, this line ends into a goofy conical "T" fitting: one line came from the cruise control diaphram; one goes into the vacum valve I've replaced and one very thin line goes somewhere, but I can't tell.
It's not listed on my diagram and not in my manuals, and we couldn't find it in the parts catalog at the dealership.
Thanks again, Mike
I located the vacum lines from the Cruise Control diaphram.
One line disappears below the booster of the Master Cylinder. I'm guessing that's okay as it didn't trickle free.
The second line ran to a standard T - one line heads off to the fuel canister, and the second line heads up toward the vacum valve I've replaced on the intake.
However, this line ends into a goofy conical "T" fitting: one line came from the cruise control diaphram; one goes into the vacum valve I've replaced and one very thin line goes somewhere, but I can't tell.
It's not listed on my diagram and not in my manuals, and we couldn't find it in the parts catalog at the dealership.
Thanks again, Mike
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
If its what I'm thinking it is....
Th goofy looking T should run to a small black check valve. That valve runs into a wiring loom that goes inside the firewall and services the heater / AC controller in the car, providing it with a vacuum source. It's more like a hard plastic line, as opposed to rubber. The other end runs to the cruise control servo and the vacuum cannister by the left front nose of the car. If the check valve is bad, they can be had from Chevy for around $6.
I lost vacuum on the line for the heater control unit, and because of the complexity of running a new line through the original loom, opted to drill through the firewall and run a new vacuum line.
Hope this helps.
Th goofy looking T should run to a small black check valve. That valve runs into a wiring loom that goes inside the firewall and services the heater / AC controller in the car, providing it with a vacuum source. It's more like a hard plastic line, as opposed to rubber. The other end runs to the cruise control servo and the vacuum cannister by the left front nose of the car. If the check valve is bad, they can be had from Chevy for around $6.
I lost vacuum on the line for the heater control unit, and because of the complexity of running a new line through the original loom, opted to drill through the firewall and run a new vacuum line.
Hope this helps.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by mike_webb_tx
On my 1984 (auto/ac), the pewter vacum port located at the rear of the intake broke off.
RACE ON!!!
Thread Starter
Advanced
Joined: Oct 2002
Posts: 55
Likes: 0
From: San Antonio TX
I would have postd a pic, but I'd be embarassed as I'm still cleaning all the dust from the idler pulley that buzz-sawed itself off the mount and shredded the serpetine belt (at 5500RPM-- ka-CHUNKA shred shred shred thunk clatter...)
What I really need are sticky tires so I can recapture SM2 class next year at our autoX :P. However, the last few posts are dead on, it has to be the hard line to the a/c. And off I go.
Thanks all, Mike
What I really need are sticky tires so I can recapture SM2 class next year at our autoX :P. However, the last few posts are dead on, it has to be the hard line to the a/c. And off I go.
Thanks all, Mike