Topic: fastest best way to create return line for gas tank EFI setup

[biggrgivens]

Ok, I was just going to swap a bigger new mustangII gas tank on my 72 pinto. I just noticed that the previous installer when going EFI, that he used the vent as return line. I want to use vent as a vent. what is the fastest yet efficient way to return fuel to tank? Do I need to tig in a new return? Can I just drill a hole in new tank and install another crank vent as mod to use as return tube?

[dianne]

Ok, I was just going to swap a bigger new mustangII gas tank on my 72 pinto. I just noticed that the previous installer when going EFI, that he used the vent as return line. I want to use vent as a vent. what is the fastest yet efficient way to return fuel to tank? Do I need to tig in a new return? Can I just drill a hole in new tank and install another crank vent as mod to use as return tube?

Does the gas tank setup need to be done differently on the 2.3 EFI?

[biggrgivens]

It needs a fuel return line unlike a carbed car.

[76hotrodpinto]

I've heard of people putting the hole through the sending unit mounting plate, rather than the tank.

[Wittsend]

I put a return line in through the sending unit. I drilled a hole, put a tightly fitting piece of steel tubing in and soldered it to seal it.  A few points to know:

1. The sending unit nylon seal for the wire melted and I liberally used JB Weld to seal it again.  5 years later it is still holding.

2. I would allow the return line to cross over or run parallel to the existing pick up line and solder it where it does. This allows additional brace points so the pass through point isn't the only point of connection.

3. I would make sure the return line didn't splash into the pick up area.  When the tank is low you don't want it pushing fuel away from the pick up.


Lastly, do at your own risk.

[76hotrodpinto]

Just tape a hose up the side and in to the filler cap, done deal! Use the shiny tape so it looks professional.

[amc49]

Build a cup of sorts around the pickup tube and then run the return into it, how modern cars are essentially built. The return serves to keep the pickup cup area full of fuel during turns when a major amount slides away from inertia and with low fuel level. All modules do that now. Many return bypassed fuel right there rather than coming all the way back from front of car.

[dianne]

Build a cup of sorts around the pickup tube and then run the return into it, how modern cars are essentially built. The return serves to keep the pickup cup area full of fuel during turns when a major amount slides away from inertia and with low fuel level. All modules do that now. Many return bypassed fuel right there rather than coming all the way back from front of car.

My Spitfire has something like that with a larger tank on top. I can replicate that amc! Thanks!

[76hotrodpinto]

Is there nothing a shot glass can't fix?!

[pinto_one]

I have done it a couple of times using aircraft bulkhead fittings , you can place them on the sending unit or dill a hole in the tank to use them, AN832 straight  fitting or AN833 Elbow, or last a AN807 if you just want to hook a hose to it , and use the nut AN924 to back it up,   a dash number at the end of the number gives the size , 1/8 to 3/4 ,  and Dianne I will send you the fed ex shipping number when I drop off your stuff tomorrow,  and also I included the above fittings for your fuel tank,  its amazing
how many aircraft parts end up on my cars 

[dianne]

Is there nothing a shot glass can't fix?!

So it doesn't have to be as complex as the Spitfire?

[amc49]

Dunno what Spitfire looked like but the ones I've seen have a small demand valve or poppet that stays closed until pump demands fuel, it then slips open to let fuel in. On a Focus say, it is only a flat round piece of silicone rubber that lifts instantly on demand but then closes so fuel stays pretty much trapped in the reservoir cup there.

You want instant availability of fuel when needed but cup seals off at fuel sloshing time like cornering. The in-tank pump output has a small amount short-circuited off in a bypass that spills right back into cup to help keep it full.

[dianne]

Is this something I can pull from a fox body?

[amc49]

If talking Ford parts, in my limited knowledge those type reservoirs started being used say '99-'00 and tied to higher pressure MPFI pumps, of course the reservoir does not care about pump other than if the internal bypass is used it will be rated with a higher pressure check valve based on around 45 psi. Reservoir would not care as well about whether the bypass fuel coming back came from right there in a short loop or all the way from front of car.

[pintoguy76]

I stumbled across this thread just now. I thought the second (smaller) line in the fuel sending unit WAS a return line, but you guys are saying that its actually a vent line? I have a 91 Mustang 2.3 DIS in my car. Is this causing me any problems that I am unaware of? Come to think of it, there is a 3rd line up front on the frame rail that I had to cap off, its connected to the fuel system somehow... where could it be coming from? And which one would be the vent and which one would be the return? Car is a 74 wagon, 2.3....

[65ShelbyClone]

I don't know why there would be three lines, but I would guess that at least one was a vent and went to the charcoal canister.

I used the vent as a return by making an aluminum piece to replace the pot metal original (that has a tiny restrictor in it to let vapor out, but not be significant fuel flow path).


It would have been simple to put two fittings in it and keep the original vent configuration. I ditched the charcoal canister when I went 2.3T EFI, so it would have been more work just to preserve a vent line to nowhere.