fuel venting

[Ken B]

OK so I need help( such a loaded statement). I am trying to get my fuel system vented. 1981 c10.
I have a 2 port sending unit in the gas tank. 1 out , 1 return.
I have a mechanical fuel pump, 1 inlet 1 return and one line running up to the carb.
My problem is memory is terrrible.
The vent , how does it run where does it connect?
It appears it connects to the vapor cannister behind the headlights and a steel line runs across the front under the radiator. it then goes where????
I have read a couple of things that says the vent connects to the fuel filler neck, the highest point of the system.
Thanks for any input

 

[Grit dog]

I think someone replaced the fuel sender with an early 2 port model.
AFAIK by late 70s they were 3 port.
Is there a problem you’re trying to solve or just thinking maybe your tank isn’t vented?

 

[Ken B]

I am worried that thereisnt a vent.

 

[legopnuematic]

My 76 is two port senders, fuel pump with in and out (returnless), charcoal canister.

Feed from sending units to switching valve, then to fuel pump, to carb.
From carb to charcoal canister, to hardline, teed to other port on senders.

My 79 is a single tank truck, three port sender, fuel pump with return, and charcoal canister.

The 85 I parted out was the same as the 79.

 

[Ken B]

I have fuel in and out of fuel pump and to carb done, i think. I have a hard line that runs across the front to charcoal canister and to the rear of the truck where do I land that hard vent line from the canister?

 

[Ken B]

so what I am looking at doing is cutting in a T on the fill hose vent line to attach my return vent from the charcoal cannister....is this a good or bad idea ? obviously would need something compatible with gasoline .
Looks like maybe a 3/4 vent hose for fuel filler....

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[Old Guy Bill]

I’d put a three line pickup/sender unit in it…

 

[Ken B]

I wish I could. Old pic. Already got cab on. And would prefer not to drop tank

 

[Ricko1966]

I wish I could. Old pic. Already got cab on. And would prefer not to drop tank

I'd pull the fill tube and braze in a piece of steel tubing of correct size and bent accordingly.

 

[Grit dog]

Wonder if you can’t find a vented filler cap, or make the OE cap fully vented?
And yes the line from the evap can towards the rear is likely what should be plugged into the 3 port fuel sender.

 

[Randy and Easton]

OK so I need help( such a loaded statement). I am trying to get my fuel system vented. 1981 c10.
I have a 2 port sending unit in the gas tank. 1 out , 1 return.
I have a mechanical fuel pump, 1 inlet 1 return and one line running up to the carb.
My problem is memory is terrrible.
The vent , how does it run where does it connect?
It appears it connects to the vapor cannister behind the headlights and a steel line runs across the front under the radiator. it then goes where????
I have read a couple of things that says the vent connects to the fuel filler neck, the highest point of the system.
Thanks for any input

Ken,

we had same issue. PO did the charcoal canister delete 2 port sending unit as well. Found that same steel line under radiator shroud and PO cut it drivers side bottom and that was it. We smelled gas all the time and could not find at the time a canister. I made a small charcoal filter out of a fuel filter and a fuel vent and mounted it on drivers side firewall. Fixed the gas smell and have never looked back.

Not sure if that is what your wanting but here are a few pics

Randy and E

 

[labratm]

I need to make one of those. What did you use for the charcoal?

 

[Ken B]

Looking to get this plumbed up. This is a swap 250 to 350 so my core has the old routing. Where do these land? Or where can I find the routing. Please and Thanks

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[Ricko1966]

Your bighose at 5oclock goes to a tee in the pcv hose. The little one tees into small hose on next port up. Little hose on 5 o'clock post goes to ported vacuum. Big hose on middle port,goes to carbureator bowl vent. 2nd from top port goes to fuel tank vent. Very top port goes to air cleaner.

 

[SquareRoot]

I need to make one of those. What did you use for the charcoal?

Charcoal