Gas Tanks
Thread Starter
|
Senior User
Joined: Jan 2000
Posts: 101
Likes: 1
Gas Tanks
Hey Ya'll,
Is there supposed to be a "pressure build up" in the gas tank that gets relieved by the gas cap or that gizmo thats connected to the line that goes to the canister?
I can't get a good enough flow from the tanks, I've pulled both and removed the socks, front tank runs dry with 6gal. left and the rear runs dry with 11gals. left in the tank. I can tell when I'm runnin low, the fuel pump gets loud and when I switch to the full tank the fuel pump gets quiet and the truck runs great for awhile. I think I'm gonna plug the small line (from the tanks) at the canister and unplug the vent line to the carb. I'm really poking around in the dark now....
Moe
302 orig 300/6
I don't think there's a difference in the gas tanks...but I could be wrong.
Is there supposed to be a "pressure build up" in the gas tank that gets relieved by the gas cap or that gizmo thats connected to the line that goes to the canister?
I can't get a good enough flow from the tanks, I've pulled both and removed the socks, front tank runs dry with 6gal. left and the rear runs dry with 11gals. left in the tank. I can tell when I'm runnin low, the fuel pump gets loud and when I switch to the full tank the fuel pump gets quiet and the truck runs great for awhile. I think I'm gonna plug the small line (from the tanks) at the canister and unplug the vent line to the carb. I'm really poking around in the dark now....
Moe
302 orig 300/6
I don't think there's a difference in the gas tanks...but I could be wrong.
Guest
Posts: n/a
Gas Tanks
I've got an '84 E-150 w/ dual tanks. Originally had the 351W, I put in my '83 300 (don't ask why).
It sounds like yours is not getting enough positive vapor pressure from the canisters. I haven't fiddled much with the evaporative control stuff, but it's possible that something's plugged up between the canisters and your tanks.
Mine does the opposite. For some reason the rear tank gets a lot of pressure. I don't know if it's from the fuel sloshing or heat or what. But that positive pressure above the fuel isn't being released and it causes fuel to flow through my mechanical pump even when the engine's not running.
I think it's killing my gas mileage. I've got other things to worry about on the van right now so I haven't really looked into the problem.
Is yours mechanical or elecric pump?
It sounds like yours is not getting enough positive vapor pressure from the canisters. I haven't fiddled much with the evaporative control stuff, but it's possible that something's plugged up between the canisters and your tanks.
Mine does the opposite. For some reason the rear tank gets a lot of pressure. I don't know if it's from the fuel sloshing or heat or what. But that positive pressure above the fuel isn't being released and it causes fuel to flow through my mechanical pump even when the engine's not running.
I think it's killing my gas mileage. I've got other things to worry about on the van right now so I haven't really looked into the problem.
Is yours mechanical or elecric pump?
Thread Starter
|
Senior User
Joined: Jan 2000
Posts: 101
Likes: 1
Gas Tanks
>I've got an '84 E-150 w/ dual
>tanks. Originally had the 351W,
>I put in my '83 300
>(don't ask why).
>It sounds like yours is not getting
>enough positive vapor pressure from the
>canisters. I haven't fiddled much
>with the evaporative control stuff, but
>it's possible that something's plugged up
>between the canisters and your tanks.
>
>Mine does the opposite. For some
>reason the rear tank gets a
>lot of pressure. I don't
>know if it's from the fuel
>sloshing or heat or what.
>But that positive pressure above the
>fuel isn't being released and it
>causes fuel to flow through my
>mechanical pump even when the engine's
>not running.
>I think it's killing my gas mileage.
> I've got other things to
>worry about on the van right
>now so I haven't really looked
>into the problem.
>Is yours mechanical or elecric pump?
I have a cheap-*** purolator electric pump, I had to take off the nice Carter 4070 cause the truck would only idle with it.
I've decieded to pull the rear tank today and replace the fuel line, sock, fuel selector valve, and go to Pick-A-Part and find a FI rear tank with a "in tank" pump. Jesus! Replacing the entire engine from a 300/6 to a 302HO was the easy part.
Moe
85 F150 302 orig. 300/6
Houston
>tanks. Originally had the 351W,
>I put in my '83 300
>(don't ask why).
>It sounds like yours is not getting
>enough positive vapor pressure from the
>canisters. I haven't fiddled much
>with the evaporative control stuff, but
>it's possible that something's plugged up
>between the canisters and your tanks.
>
>Mine does the opposite. For some
>reason the rear tank gets a
>lot of pressure. I don't
>know if it's from the fuel
>sloshing or heat or what.
>But that positive pressure above the
>fuel isn't being released and it
>causes fuel to flow through my
>mechanical pump even when the engine's
>not running.
>I think it's killing my gas mileage.
> I've got other things to
>worry about on the van right
>now so I haven't really looked
>into the problem.
>Is yours mechanical or elecric pump?
I have a cheap-*** purolator electric pump, I had to take off the nice Carter 4070 cause the truck would only idle with it.
I've decieded to pull the rear tank today and replace the fuel line, sock, fuel selector valve, and go to Pick-A-Part and find a FI rear tank with a "in tank" pump. Jesus! Replacing the entire engine from a 300/6 to a 302HO was the easy part.
Moe
85 F150 302 orig. 300/6
Houston
Senior User
Joined: Jun 1999
Posts: 366
Likes: 0
From: saramento usa
Gas Tanks
Moe,
I think you're on the right track with the fuel vent to the canister. I believe that this is a vent for the tank that flows to the carbon cannister. The carbon cannister is supposed to trap the fumes when the route to the carb is blocked off during acceleration or warm up. Do you still have the plastic pots inline in the vent hose (between carb can and vacuum cannister). Maybe if it isn't venting properly then it acts almost like it is creating a vacuum that is trying to hold the gas in the tank. I'm just shooting at holes in the dark on this one, but it seems like it has to do with something on that vent system.
Slik
I think you're on the right track with the fuel vent to the canister. I believe that this is a vent for the tank that flows to the carbon cannister. The carbon cannister is supposed to trap the fumes when the route to the carb is blocked off during acceleration or warm up. Do you still have the plastic pots inline in the vent hose (between carb can and vacuum cannister). Maybe if it isn't venting properly then it acts almost like it is creating a vacuum that is trying to hold the gas in the tank. I'm just shooting at holes in the dark on this one, but it seems like it has to do with something on that vent system.
Slik
