Fuel return line?

[blthomas]

Working on the gas tank on our 81'.

I know it's fed up the passenger side to the pump on this and my CJ7'.

I have a return line all by itself on my CJ7, it runs near my hard brakeline on the frame.

On the CJ8, there is the hard brakeline, then 2 hard lines running next to it. One of those lines is rusted all the way through and I have yet to see anything wet near it.

Is this line part of the emissions plumbing, and if so can I delete it as I take off the rest of the emissions plumbing?

There is so much crap caked up under there I haven't found where it goes, and my 7 has been molested so much it's a poor example to follow.

That and 30 years of mud hides alot.

 

[walkerhoundvm]

One of those is the fuel return line, the other is a line running from the rear check valves to the canister. I'm guessing your canister is going away, and your check valves are no where to be found? A common way that people rig this is to loop a line between the two ports on the 15g tank that originally went to the check valves, and that sometimes works. Of course, it's harder for the tank to vent vapors other than into the environment that way.

Not that you have to do it this way, but I kept my canister and plumbed the check valves after fixing/replacing them, routing a hard line between the valves and the canister. I run a TBI and still have the canister incorporated into the system.

 

[Danimal713]

well not to hijack the thread but sounds like you could use a diagram too. Does anyone have a nice diagram or pictures showing the proper fuel line routing? It would be most helpful.

 

[John N]

This may help....

 

[blthomas]

Thanks guys, pic is worth a thousand words.

Interesting, got the new tank in and plumbed, I went ahead and replaced all lines at tank.

I crawled under the CJ7 and the check valves are still up under there in the rear. The canister is still up front on the 7, I should rephrase and say not alot goes to it.

On the 8, it looks like from John's pic, the return line from the fuel filter is the rusted open one.

It is currently clogged with mud, so that may explain why it doesn't drip when the Jeep runs.

Dying to drive it, got the new tank on, new shocks and stabilzer, and welded in a new muffler and pipe to replace the rotted out cat and muffler that were factory.

I'm going to go splice in a rubber piece on the return line just to be safe. OUt of curosity how much fluid would be running back to the tank?

Thanks very much.

 

[walkerhoundvm]

I'd be surprised if it is the fuel return line, it'd be worth replacing if it is. You need some relief from back pressure to allow the carb to run right. I'd be more inclined to think it was the line from the check valves to the evaporative canister - mine was plugged with charcoal from the canister and I had to replace it.

 

[Otto]

I know its been along time since I dealt with carbs, but don't they have float/valve to shut off excess fuel flow? So that other pipe is vapor for the fuel canister.
John N, that is a great picture, and do you have one for the 20g tank?

 

[John N]

John N, that is a great picture, and do you have one for the 20g tank?

No and I really can't take credit for this picture. Someone posted it on another forum and I saved it, it looked like something I might be able to use at some point.

 

[Danimal713]

And you were right! It came n handy for you & for us! Thanks.

 

[blthomas]

I haven't done anything but drive it around. The rusted line full of mud is in place, and waiting for me to replace it. That said, no fuel leakage, Jeep runs good and strong so it must be a evap line.

Thanks for the help, working on the 7 alot right now, will be back to work on the 8 soon enough.

 

[jeepbob]

Anyone know where to get a liquid check valve? I got the rollover check valve from DMC. The liquid check valve I have has had one of the ports broken off of it. The one broken off is the one that runs into the rollover check valve.

 

[walkerhoundvm]

I used a $2 brass fitting from Ace and some two-part epoxy to fix mine. It's doable, or maybe you can find one that's complete - they come on the market a couple times a year

 

[John N]

Picture disappeared for some, so here it is again.

 

[DOJOLOACH]

Picture disappeared for some, so here it is again.

Hey John, Is that black bracket with the check valve and other components actually mounted right there? Or was this just for educational purposes?

I'm trying to plumb my 8, with a carbed amc360

 

[ag4ever]

Just as an FYI, that picture is the 15 gallon setup. The 20 gallon poly tank has vents that pop into holes in the top of the tank.

 

[DOJOLOACH]

Just as an FYI, that picture is the 15 gallon setup. The 20 gallon poly tank has vents that pop into holes in the top of the tank.

Thanks, I'm working with a 33g tank though. It has two vent holes out the driver side and an additional smog hole on the top of the tank

 

[John N]

Hey John, Is that black bracket with the check valve and other components actually mounted right there? Or was this just for educational purposes?

I'm trying to plumb my 8, with a carbed amc360

That was someone else’s picture that I saved. There is a bracket like that in the driver’s side rear wheel well that they mount to with a 15 gallon stock tank.