In tank EFI fuel pump.

68rustang

Active Member
Jan 17, 2003
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Cleveland, OH
Just wanted to get some feedback on a little idea I came up with this morning. I was going to cut the top out of my gas tank to do an in-tank pump. I was comparing the 68 sending unit/pick-up to the in-tank pump/pick-up from my 95 parts car. While looking at them I thought why not just re-orient the 95 so it resembles the 68 but incorporates the fuel pump?

This is what I came up with:

sending_unit_1sm.jpg


sending_unit_2sm.jpg


Right now it is just tacked together. If I decide I am going to keep it I will either make a new bracket out of stainless or TIG this one up Monday at work.

I don't think I can fit the fuel level sender on the assembly and still get it to fit through the hole. I will have to figure that out later.

Does it matter if the pump is not straight up and down? It looks like I will not have starvation issues any worse than they would be with a stock pick-up. What do you guys think?
 
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Tried it, didn't like it. I had problems sealing the pass throughs for the pump power and ground, and the return line. Also the pump wouldn't pick up fuel unless there was at least 4-5 gallons in the tank.

I ended up going external with a low pressure feeder pump into a surge tank, then to the hi pressure. Eliminates starvation on hard corners, and allows me to use a stock sender and tank.
 
With no baffles in your tank you will be very unpleased with the results. I toyed with the idea you have displayed but quickly realised it wasn't going to work correcty. You need baffles or a header tank.

I prefer intank pumps so I made my own system that allows me to change pumps with a full tank of gas on the side of the road, standing up, in about 30 minutes.

http://pg.photos.yahoo.com/ph/hertzshelby66/album?.dir=/6fdb&.src=ph&.tok=phetV7DBilUB1kvG
 
Ronstang said:
With no baffles in your tank you will be very unpleased with the results. I toyed with the idea you have displayed but quickly realised it wasn't going to work correcty. You need baffles or a header tank.

I prefer intank pumps so I made my own system that allows me to change pumps with a full tank of gas on the side of the road, standing up, in about 30 minutes.

http://pg.photos.yahoo.com/ph/hertzshelby66/album?.dir=/6fdb&.src=ph&.tok=phetV7DBilUB1kvG

Your project is what gave me the idea initially. I am going to almost copy your design. I came up with this while brainstorming other ideas before I actually cut my brand new gastank. I realize it is not perfect but it should allow me to get the car running. I thought about it some more after I posted the pics and without baffles or a way to get the sending unit in there it really is just a temporary thing. I don't like the idea of two fuel pumps.
 
rbohm said:
i agree with the others, building you own in tank pump is going to be a pain when dealing with issues like sealing electrical connections and such.

I don't see where the pain would come from. The tank is new never had gas in it so welding won't be a problem. Welding a fluid tight tank isn't a big deal, it is part of what I do for a living. The electrical connections are a simple matter of little holes and little o-rings.
 
Another thing I have done is cut open brand new tanks and then welded baffles in them for the stock sending units to work with so you can run simply one external pump. I did this on an 86 Bronco I helped a friend with. I used a baffle out of an old Fox body Mustang for time's sake instead of building something from scratch because in the Bronco's gas tank it worked fine. No problems getting the tank to seal again after welding the part I cut out back in. It never leaked and that was 4 years ago and the vehicle has been running fine with fuel injection ever since. There are many ways to skin a cat.
 
Ronstang said:
Another thing I have done is cut open brand new tanks and then welded baffles in them for the stock sending units to work with so you can run simply one external pump. I did this on an 86 Bronco I helped a friend with. I used a baffle out of an old Fox body Mustang for time's sake instead of building something from scratch because in the Bronco's gas tank it worked fine. No problems getting the tank to seal again after welding the part I cut out back in. It never leaked and that was 4 years ago and the vehicle has been running fine with fuel injection ever since. There are many ways to skin a cat.

Do you by chance have any pics of the baffles? If not could you describe what they look like or how they are installed? I am going to be running an inline pump and need to do something with regard to baffles.
 
rhyno9 said:
Do you by chance have any pics of the baffles? If not could you describe what they look like or how they are installed? I am going to be running an inline pump and need to do something with regard to baffles.

Look at the pics of my tank I listed earlier in this thread. That is a homemade baffle which was based on a plastic baffle I pulled out of a Taurus SHO tank, I could not make the plastic one work to my liking so I made my own. The one I installed in the Bronco tank was simply taken directly out of a 90 Mustang's tank. Baffles vary from one car to another but all provide the same function. If you cannot get a good idea from my pics then go to a Pick-N-Pull style salvage and look as some examples in the late model section. I did my research at the salvage yard before I built my tank.
 
CochinoFilipino said:
How did you prep the tank interior after welding? Did you just coat the welded areas or seal the whole tank with a certain sealer.

I didn't do anything on the inside since it was not easy to get in there after I finished. This was over three years ago. We are about to transfer the EFI setup from that 1986 Bronco to the 1973 Bronco my buddy just bought so I will take the tank I modified and cut it open to get the baffle and I will see just what has happened inside the tank. If you are worrying about the welds rusting I would worry about the seam weld on the stock tank rusting out first, but if you are concerned then you can always use the tank sealing kit from Eastwood.