Suburban/Blazer tank conversion / return line port

[D-n-Tyke]

Does anyone know how far over the fill tube flange goes inside the tank. I need to add a fuel injection port to this tank but am worried I am going to hit the edge of fhe flange inside the tank. I want to put one of those swag in port fittings but if it lands on half the flange I don't think it will seal right.

My plan is to put it right u der the vent pipe. Approximately where the red dot is.

Anyone have experience with these tanks and no where the flange ends.

[D-n-Tyke]

This is the fitting I am trying to install.

[Palf70Step]

I believe the return line connection would be in the sending unit. Not sure what year it started, maybe 72.

[Bigdav160]

My return line port is part of the sender/fuel pump module

[HO455]

I added a return line to my 67 Burban's tank by soldering an other tube in the sender. Easier to get a solid leak free joint and safer too as I wasn't heating the tank. I've done this successfully on several vehicles. You can save the $20 for some beers.
See the link and post 377 for what I did.


http://67-72chevytrucks.com/vboard/s...698377&page=16

[D-n-Tyke]

Originally Posted by Palf70Step

I believe the return line connection would be in the sending unit. Not sure what year it started, maybe 72.

Originally Posted by Bigdav160

My return line port is part of the sender/fuel pump module

Yes the later model years have a evap and then later evap and return ports in the sending unit. I am working with a 1969 tank and there is only a supply line in the sending unit.

Originally Posted by HO455

I added a return line to my 67 Burban's tank by soldering an other tube in the sender. Easier to get a solid leak free joint and safer too as I wasn't heating the tank. I've done this successfully on several vehicles. You can save the $20 for some beers.
See the link and post 377 for what I did.


http://67-72chevytrucks.com/vboard/s...698377&page=16

This is perfect. That is where I originally wanted to put the return line but didn't think there was enough room. Although I was trying to fit the adapter above into the sending unit. I don't know why I didn't think of soldering in another tube.
Where did you end up getting the 5/16 tube from? What type of metal is the tube you used?
Thanks for the suggestion. I owe you a beer from that saved $20.

[HO455]

Originally Posted by D-n-Tyke

This is perfect. That is where I originally wanted to put the return line but didn't think there was enough room. Although I was trying to fit the adapter above into the sending unit. I don't know why I didn't think of soldering in another tube.
Where did you end up getting the 5/16 tube from? What type of metal is the tube you used?
Thanks for the suggestion. I owe you a beer from that saved $20.

The tubing is regular 5/16 steel fuel line available at most parts houses or can it be scavenged from a parts car.

[D-n-Tyke]

Originally Posted by HO455

The tubing is regular 5/16 steel fuel line available at most parts houses or can it be scavenged from a parts car.

Thanks HO455! Following your suggestion, and your pictures, I was able to add the 5/16 return line into the sending unit. I wasn't able to put it in the exact same spot yours went in but found a good spot just the otherside of the original feed line. I didn't like how mine ended up without any support inside as I plan on using a rubber hose inside to attach another piece of bent tubing to the return line so it will ultimately return the fuel in the opposite side of the tank from the pick up. To help with support I added a little cross brace to attach the 2 tubes together. Not my best soldering job but should hold.

[HO455]

You're welcome. Nice work, it looks good.

I would think twice before putting a piece of hose inside the tank. It will eventually disintegrate and end up being sucked into the sock.

[biketopia]

Originally Posted by HO455

You're welcome. Nice work, it looks good.

I would think twice before putting a piece of hose inside the tank. It will eventually disintegrate and end up being sucked into the sock.

To piggy back on this, if you do put hose in, do not use regular old fuel hose!! You need to use submersible fuel hose, it can be a little more difficult to source and is is about $15+ a foot. Hopefully you didn't get any sort of pin hole in the fed or return with your cross brace. Good idea though!

[D-n-Tyke]

Originally Posted by biketopia

To piggy back on this, if you do put hose in, do not use regular old fuel hose!! You need to use submersible fuel hose, it can be a little more difficult to source and is is about $15+ a foot. Hopefully you didn't get any sort of pin hole in the fed or return with your cross brace. Good idea though!

Any suggestion on sourcing the submersible fuel line?

Shouldn't have gotten an pin holes. Main tubes (feed and return) were not cut/touched. I just slide a scrap piece of tube between the two main tubes snd then soldered it in with low heat. I don't think that would have created any additional holes.

[RustyPile]

Originally Posted by D-n-Tyke

Thanks HO455! Following your suggestion, and your pictures, I was able to add the 5/16 return line into the sending unit. I wasn't able to put it in the exact same spot yours went in but found a good spot just the otherside of the original feed line. I didn't like how mine ended up without any support inside as I plan on using a rubber hose inside to attach another piece of bent tubing to the return line so it will ultimately return the fuel in the opposite side of the tank from the pick up. To help with support I added a little cross brace to attach the 2 tubes together. Not my best soldering job but should hold.

You're over thinking this project.. The more pieces you add to the sending unit the more problems you'll have feeding all that "stuff" through the hole in the tank.. Any rubber hose will eventually deteriorate, fall off, and block the float travel and pickup sock. What you have now is good enough, put it in and move to the next project.

[D-n-Tyke]

Originally Posted by RustyPile

You're over thinking this project.. The more pieces you add to the sending unit the more problems you'll have feeding all that "stuff" through the hole in the tank.. Any rubber hose will eventually deteriorate, fall off, and block the float travel and pickup sock. What you have now is good enough, put it in and move to the next project.

I am concerned with the fuel being returned to the tank right next to the pick up being aerated. With the pump being external and all that comes with that I don't want to add running aerated fuel thru it to what it has to overcome.

[HO455]

Maybe soldering a 90 to the end of your existing return would get you what you want. (See crudely drawn 90 in photo) If the 90 points away from the pickup sock then the aerated fuel would be sent away from the pickup and you should still be able to install the pickup assembly and avoid rubber in the tank.

Fortunately gasoline is very thin and air dissipates quickly.

[D-n-Tyke]

Originally Posted by HO455

Maybe soldering a 90 to the end of your existing return would get you what you want. (See crudely drawn 90 in photo) If the 90 points away from the pickup sock then the aerated fuel would be sent away from the pickup and you should still be able to install the pickup assembly and avoid rubber in the tank.

Fortunately gasoline is very thin and air dissipates quickly.

That is an idea I. Can look into more.

How did you end your? Just go start down with yours? Have you had any issues with aeration?

[Richard]

Not sure what the problem is dumping the return next to the feed? A 90's Blazer or Suburban with fuel injection dumps return right next to the feed to fill the bucket surrounding the pump pickup. I am using a 90's Blazer tank and was going to use that setup but went a different direction with my LS swap, a stock type PWM deadhead system that is original to the motor I am using. On another note the factory in-tank fuel pump on those vehicles are connected to sending unit via a rubber fuel line. Same as my 1994 truck.

[biketopia]

You're fine to dump the return near the pick up, most EFI set ups do that from the factory. Also, don't be afraid to run rubber inside the tank if it's the right stuff, also been done for decades on the OE level.... That being said either look at the gates hose part numbers, or quantum fuel supply. They have the corrugated fuel hose most newer vehicles use, either solution will be fine.

https://www.gates.com/us/en/fluid-po...00-000012.html

https://www.highflowfuel.com/catalog/fuel-hose-clamps/