Aftermarket Sending Unit with Return Line

[wphilli1]

Hi Guys,
I am currently looking at installing the Fitech EFI system on my '58 Apache with 355 SBC. I'm trying to take care of all the details before I order it, and am stuck on the fuel return line. I know I could use the Fuel Command Center sump system that they sell, but I'd rather not have that in my engine compartment due to fitment and just that I don't think it would look right. So, my question is; are there any aftermarket sending units that fit our trucks that have a return line built in, or do any of the later model 2 or 3 line sending units fit in our tanks?

Thanks in advance and Happy Motoring,
Wylie

[dwcsr]

Originally Posted by wphilli1

Hi Guys,
I am currently looking at installing the Fitech EFI system on my '58 Apache with 355 SBC. I'm trying to take care of all the details before I order it, and am stuck on the fuel return line. I know I could use the Fuel Command Center sump system that they sell, but I'd rather not have that in my engine compartment due to fitment and just that I don't think it would look right. So, my question is; are there any aftermarket sending units that fit our trucks that have a return line built in, or do any of the later model 2 or 3 line sending units fit in our tanks?

Thanks in advance and Happy Motoring,
Wylie

I'm assuming you asking about the stock behind the seat and no so far as I know they do not make a sender with a return.

The issues is the fuel cup required for EFI to function properly and not suck air on corners and hard stops and acceleration. This is the reason they use a command center, you don't need to change your pickup tube or fuel tank.

I have heard that there are issues with the FItech command center but don't have first hand experience so I don't know if its wrong installation or bad product causing the fuel issues with FItech command center. You could do a search on "Fitech command center problems" they appear not to be resolves as of June this year.

The other option is an actual EFI tank under the bed with a return.

[wphilli1]

Yeah, I am talking about the stock tank behind the seat. From what I've read, because the tank it vertical the fuel starvation on turns is lessened a lot and shouldn't be an issue above 1/4 of the tank being full. I was thinking either about plumbing the return line into the fuel filler tube as I have seen done else where, or soldering an extra tube into the sending unit. If I go the sending unit route I was going to go for a new one just so the solder job works better and I won't have to do it again in a few years of the original one eats it.
Thanks for the response,
Wylie

[mr48chev]

I'd go along with plumbing a return line into the filler tube or vent line. You might be able to plumb a T into the vent line pretty easy and that normally only vents the tank when you are filling it so it wouldn't be an issue when it was running.

[wphilli1]

The only issue I've heard with that is it may aerate the fuel and cause cavitation and cause a lot of fumes in the cab and also some people claimed that might cause a static charge, but I don't think that's an issue. Moroso sells a kit for that specifically, but I'll have to cut the filler tube. Does anyone have any experience with this kit or one like it?

https://m.summitracing.com/parts/mor-65385

[01spirit750]

wphilli1- I do not post a whole lot but I just completed doing exactly (for the most part) what you are asking about. I know you do not like the surge tank but it was the best option for me. I had read about issues with fuel starvation due to fuel sloshing in the tank. With an intank EFI fuel pump I was told you must have baffles installed or once you get to half a tank you will have issues. external fuel pumps can be noisy and people have had issues with them.

I am running the EZ EFI 1.0 system.

I will take a picture of my sending unit and post / send it tonight.

Here are the details:
I had looked at the surge can options and I chose the one from robmcc and it has been working fine. The robb mc one uses your factory low pressure pump to supply fuel to the surge tank.
http://www.robbmcperformance.com/pro...owersurge.html

You still have to run a "vapor" line back to your tank.

What I did was to buy a new sending unit and add a return line (vapor) to it. I had to buy a new one because I would be silver soldering the return line. A used sending unit would go up in flames due to the gas residue.

I installed the surge tank on the radiator support.

I bought the silver solder and acid from ebay.
http://www.ebay.com/itm/262308653784...%3AMEBIDX%3AIT

New sending unit. I drilled another hole and then temporarily removed the electrical connector while I solder it in.
http://www.ebay.com/itm/262266347428...%3AMEBIDX%3AIT

I bought a prebent line with a loop and cut off the end without the flare nut to solder it to the sending unit. I was running a hardline all the way to my surge tank.

http://www.ebay.com/itm/252317014661...%3AMEBIDX%3AIT

[wphilli1]

Spirit,
Thanks for sharing that sump tank with me, it looks a lot less obtrusive than the fitech one, and smaller/cheaper. I will definitely consider going that route as it does seem to take care of all the issues with using the stock tank. I have seen some sending units with baffles built into the pickup, but only for more popular vehicles, not for our trucks.

[01spirit750]

I will take some pictures tonight and post them.

[01spirit750]

Here the pictures of the sending unit and surge tank.

[1project2many]

Yeah, I am talking about the stock tank behind the seat. From what I've read, because the tank it vertical the fuel starvation on turns is lessened a lot and shouldn't be an issue above 1/4 of the tank being full.

I installed EFI in my truck back in '92. No internet, no friendly folks on forums for guidance, and no "how to make your car EFI" books to read. I built a custom sending unit with a return line that used an S10 fuel pump and the stock float arm and resistor to install in my OEM tank. At that time I did not fully understand the considerations for fuel when building a recirculating EFI system.

To keep this simple, there is no reservoir for the engine to draw fuel from if the pump is not in fuel and there is no means to handle vapor formed as hot returning fuel sloshes in the tank. Below approximately 1/2 tank the truck would begin to show signs of fuel starving on corners and it would get increasingly worse as fuel level dropped. On long trips the cab would begin to smell of fuel as pressure in the tank forced fuel vapor out around the simple gaskets between the old sender "plate" and tank, between the new sender and tank, and between the filler neck and vent hoses and the hard metal pipes. It's taken some time to remedy this situation. I had to build a cup around the pump, had to install a cooler on the fuel return line, and I still plan to install a vapor line up to a charcoal canister. Although I say it can be done, if I were building the truck again I would put more effort into considering mounting the tank outside the cab.

When I converted my '67 Chevelle to EFI I used a "pump module" similar in function to the unit pictured above from a marine application. The marine systems often use a traditional tank and an engine mounted mechanical pump. The module has a float to control fuel delivery into the reservoir. A high pressure pump in the fuel module circulates fuel to/from the engine and a vapor line at the top allows connection to a charcoal canister or an air cleaner. I mounted this to the fender in an area where airflow would help keep it cool as some of the racers I'd spoken with at the time reported troubles with fuel becoming too hot in a small recirculating system. Mercruiser has also had some trouble with this and now makes a pretty neat fuel cooler that uses freshwater entering the cooling system to cool the fuel. Ultimately this system worked well enough that I would consider a similar system if well constructed.

The tank pictured above looks neat from the outside. Based on my experience and conversations with others that have used similar devices I would ensure the can is removed from as much heat as possible, and I would even consider using a fuel cooler (a power steering cooler might work) to help keep fuel temp reasonable. I cannot and would not say the install pictured above will have problems, but I would do my best to build in a "fix" before an issue cropped up.

[1-ton of fun]

on my Buick, i just drilled a hole in the sending unit plate and used an npt hose barb, and npt nut to secure it. might aerate some, but it works fine. i guess if you were really worried, you could extend the line down to the bottom of the tank