Vent tube with efi tank? Need your opinion Please!

-

MonkeyMadness

FABO Gold Member
FABO Gold Member
Joined
Jun 13, 2016
Messages
1,407
Reaction score
1,927
Location
Yorba Linda California
Not sure what to do. My setup has 3 vent tubes! How many do I need?
My set up is a new efi tank with intake pump/sending unit.
The tank had a vent nipple and the sending unit also has a vent nipple and the fuel neck has the stock for 65 vent tube. I have fully rebuilt the fuller neck and vent line.
I'm not running a vented gas cap, and I planed on just running the fill tube vent but as I'm getting ready to install the tank I'm second guessing my decision and could use a second opinion
Please..

2cmugso-jpg-jpg.jpg
20200523_152147.jpg
20200523_152310.jpg
20200523_152221.jpg
 
Is that a Tanks, Inc tank? I would consider buying one if they would modify it to accept a stock sending unit and just the in-tank pump. The sending units that come with it are not known for their great accuracy whereas I have 3 or 4 used stock sending unit plus a pair of NOS sending units that all test accurate.
 
I left the one on my filler tube alone. Then took a line from the tank vent and the fuel pump vent into the plastic Y in your picture. Then the single line out of the Y to the aluminum vent in your picture. Mounted it up high on the rear sub frame.
 
Last edited:
I left the one on my filler tube alone. Then took a line from the tank vent and the fuel pump vent into the plastic Y in your picture. Then the single line out of the Y to the aluminum vent in your picture. Mounted it up high on the rear sub frame.
Yes I get that, and thats my plan if I have to run all three.. but my question is, Do I need too? In theory shouldn't the filler neck vent tube be enough?
 
Yes I get that, and thats my plan if I have to run all three.. but my question is, Do I need too? In theory shouldn't the filler neck vent tube be enough?
Not sure on that. Figured it wouldn’t hurt.
 
I would think the filler neck would be all you need. These worked well. Only reason Ma changed is because of evap emissions controls starting about 70-71
 
My car didn’t have the filler neck vent or I would have used it alone. I plugged the one in the Aeromotive fuel pump and used the one off the top of the tank with the supplied vent. No problems so far.
 
By the way the nipple in the sending unit is NOT a vent. Return, maybe.
 
By the way the nipple in the sending unit is NOT a vent. Return, maybe.
No not on this pump unit. On the left in the picture with the 45* fitting is the return and on the right with the straight fitting is the sending (pump) side. The breather nipple is in the middle with a hose plug on it.
 
Yes I get that, and thats my plan if I have to run all three.. but my question is, Do I need too? In theory shouldn't the filler neck vent tube be enough?
You will be ok venting through the filler tube I blocked my tank vent and pump had a vent tube aswell, I ran mine on the filler tube no issues . I use a flip top fuel cap. I removed that flip Over valve as I couldn’t locate it high enough under the car and when I filled it with fuel It would spill out of it and I didn’t want to place it in the boot due to vapours . Just make sure that steal breather isn’t blocked on your filler tube.
 
Last edited:
I find using an evaporative emission canister works well, it keeps garage from smelling like gas. Fumes collected, are burned in purge, at cruise speeds. I do that with my EMS, solenoid valve, and canister scavenged from Dodge Omni.
 
I’m in a similar boat with a new efi tank, but no filler tube vent on the ‘74. Original vent setup is all gone too. Anyone have a picture of where they mounted the included vent? Everyone says on the frame rail, but that doesn’t seem much higher than the vent.
 
I mounted mine on my 74 as high as I could in the rear tire well.
 
I used only the tank nipple and put a plug in the pump one. No need to run both. I routed mine up by the upper shock mount and used one of the existing factory exhaust Bracket mounting holes for the attachment point so no holes had to be drilled. That’s as high as You can mount it without going into the wheel well.
 
Thanks, did you use the tank nipple or the pump nipple? Or both T’d?

I connected them with that "T" (looks more like a "Y") and ran a single line to the filter that you have pictured. Just made a simple L-bracket and mounted it in the wheel well. Was the highest point I could find that was not inside the car.
 
MM, did you work out how you wanted to run this and are you still going to run the rollover vent?
 
MM, did you work out how you wanted to run this and are you still going to run the rollover vent?

Yea, I ended up plugging the pump and top tank vents and just running the stock vent. My application needs are not drag strip or even track worthy, my needs will not be as adventuress even know I like to think they will be. I'm just in need of a setup that will work and not be complicated.
 
Yea, I ended up plugging the pump and top tank vents and just running the stock vent. My application needs are not drag strip or even track worthy, my needs will not be as adventuress even know I like to think they will be. I'm just in need of a setup that will work and not be complicated.

Bringing this thread back. In have same tank and vent setup. So you have any trouble filling up? Last night was the first time at the pump and it wouldn't stay clicked on.
 
Bringing this thread back. In have same tank and vent setup. So you have any trouble filling up? Last night was the first time at the pump and it wouldn't stay clicked on.
That has to do with "angle of the dangle", rotate filler handle to "up", use first flow notch.
 
The tank vent has very little to do with fuel filling. The divider baffle in the filler neck is the "thing" that helps filling. it is supposed to encourage air to flow back up the top side and fuel to run down the bottom side.
 
-
Back
Top