Return line question?

[Myasylum]

Well, this isn't exactly how I remembered it (Too many gas fumes).
It actually appears my gas tank was capped off and that evaporator thingy is what's left open.
I bought it this way, seem as though they didn't finish the job.

 

[71Beeper]

That sending unit is not a factory one. The factory ones never had a return line on them.
They looked like this - but not with the long extension, that's me that did that.

The return port is good to use if running an electric fuel pump.
As far as the fuel vapor separator goes, if you have the factory style one, then hook it up.
I think they are re-popped now.

 

[Myasylum]

Well, I was thinking about going to an electric fuel pump, but that's a different topic.
He does seem to have one of the 4 hooked up. They all seem to go to the same place so maybe it's good enough? Why those 3 aren't capped though is another question .

 

[kens71]

I have the same setup as 71 Beeper. My fuel line goes to a Vapor Separator Filter before going to the carb and there is a return line from that filter back to the tank. I capped all 4 hose nipples on the tank and vented the gas cap. Been working fine for 12 years with zero vaporlock. The the sending unit you have is is missing the 1/4 inch return nipple.

 

[71Beeper]

Ken, with having a vented gas cap that faces rearward, do you get any fuel leakage with hard acceleration?

 

[kens71]

I actually ended up drilling a very small hole in the center of a regular cap and there is no gas leakage. If I'm not mistaken the fill tube has a baffle at the bottom of it to keep that from happening unless the tank is overfilled.

 

[Coop]

Keep in mind if the car is parked in attached garage you are filling your home with explosive and toxic vapors. Even in a detached garage you are unnecessarily exposing yourself to risk anytime you are in there working or hanging out. Evap systems are cheap insurance for you and your families health and safety. Take your risks out the road where it’s fun and not at home while you’re sleeping.

 

[pnora]

I actually ended up drilling a very small hole in the center of a regular cap and there is no gas leakage. If I'm not mistaken the fill tube has a baffle at the bottom of it to keep that from happening unless the tank is overfilled.

View attachment 1654055

Darwin award contestant.

 

[GTXDAN]

My 70 GTX has the same system as yours which means it's a Comifornia car with the ECS (evaporation control system). The 4 lines coming from the tank all go to a vapor liquid separator area that has a line going back to the engine. On mine it goes back to the breather in the right valve cover. The return line in the sender has nothing to do with the ECS. This system also takes a special gas cap that is pressure/vacuum relief cap that I don't think you can find any more. The special cap releases when pressure reaches .5 - 1 psi or when vacuum reaches .25 - .5.
Also there is no baffle stopping gas from going back up the filler tube to the cap.

 

[kens71]

Stant made a vacuum pressure cap part number G - 47. Found them on E Bay for $10 dollars and up NOS Ordered one to stay off the Darwin Awards

 

[72RoadrunnerGTX]

The described fuel tank vapor separator change took place in April of ’72, early ‘72s used the same wheel well vapor separator/expansion tank as ’71. Two different tanks, vent nipples out the driver’s side for early and at the front of the tank for later with the small fuel tank vapor separator. The vapor recovery system was intended to provide the required fuel tank venting while using the vacuum/pressure release non-vented cap. The fifth nipple on the fuel tank vapor separator ran up to the engine compartment charcoal canister on ‘72’s. The ¼” return fitting on the pictured tank sender has nothing to do with fuel tank venting. It is correct for ’72 440s with a 3/8” fuel line, ran to a fuel line vapor separator mounted near the fuel pump originally. The functions of these systems is indeed described in detail in the FSM.

 

[RJRENTON]

Do you mix with Pepsi or Coke?

Just curious.

Some prefer Bourbon and Coke or Rum and Coke others like Pepsi and vodka.....Pepsi is a little sweeter? Personally, I like Kentucky Sour Mash Bourbon Whiskey (Jack Daniels) neet, 2-3 fingers high, with water back......
BOB RENTON

 

[kiwigtx]

Some prefer Bourbon and Coke or Rum and Coke others like Pepsi and vodka.....Pepsi is a little sweeter? Personally, I like Kentucky Sour Mash Bourbon Whiskey (Jack Daniels) neet, 2-3 fingers high, with water back......
BOB RENTON

Dark rum with dry ginger ale or coke.

 

[dadsbee]

****'s making sense now...

 

[toolmanmike]

Do you mix with Pepsi or Coke?

Just curious.

No mixing here. If I can't drink it neat, I don't want it.

 

[TopBanana72]

Keep in mind if the car is parked in attached garage you are filling your home with explosive and toxic vapors. Even in a detached garage you are unnecessarily exposing yourself to risk anytime you are in there working or hanging out. Evap systems are cheap insurance for you and your families health and safety. Take your risks out the road where it’s fun and not at home while you’re sleeping.

I agree with this. I had scary gas tank implosions (bang) and gas pouring out the filler neck on my '72 on hot days just because the prior owner dickwad capped the vent line and removed the charcoal canister. The 1972 Chrysler-designed charcoal canister/expansion tank configuration was (a Chrysler-first design, BTW) there for a reason. Respect the engineers. Stop thinking it's robbing horsepower or something!

 

[DeltaV]

Why drink bourbon when you can have Scotch?

 

[RJRENTON]

Why drink bourbon when you can have Scotch?

Depending on which Scotch.....a nice 12yo single malt, neat with water back, is wonderful although a smooth mellow charcoal filtered Black Jack Daniel's, the same way, is a nice change of pace.....either one, but it Is just the perfect way, along with your wife/partner/lady or ?? to finish out a tough day or week......but...not to excess......just a thought.....
BOB RENTON

 

[toolmanmike]

Why drink bourbon when you can have Scotch?

It's better! Ryes are better yet.

 

[toolmanmike]

Some prefer Bourbon and Coke or Rum and Coke others like Pepsi and vodka.....Pepsi is a little sweeter? Personally, I like Kentucky Sour Mash Bourbon Whiskey (Jack Daniels) neet, 2-3 fingers high, with water back......
BOB RENTON

Peefect.