EFI Fuel Hose Routing and In Tank Pump Modification

orange150

orange150

Well-Known Member
Joined
Mar 20, 2005
Location
Fairfax City, VA
Hard part of my engine build is about done (I hope; probably not) so I'm starting to worry about the next headache, fueling the EFI system.

My plan is to pick up a replacement sending unit from MTS and modify it to accept an in tank pump and return line:

MTS COMPANY, L.C. - Sending Units

Sending Units
www.mtscompany.com
1712675180445.png


The Pro Flo 4 system requires 3/8 (-6) lines and fittings, so my two main thoughts are
A) pick up two 3/8 main fuel lines from Inline Tube, one for supply and one for return
www.inlinetube.com

1981-86 Jeep CJ8 Chevrolet V8 Tank to Pump 3/8

1981-86 Jeep CJ8 Chevrolet V8 Tank to Pump 3/8" Main Fuel Line 1pc, Stainless
www.inlinetube.com www.inlinetube.com
or
B) use some -6 fuel line from Summit and use that for the entirety of the fuel system, I was thinking it would be slick to run it inside the frame rail.
www.summitracing.com

Summit Racing SUM-220985 Summit Racing™ PTFE Hose | Summit Racing

Free Shipping - Summit Racing™ PTFE Hose with qualifying orders of $109. Shop AN Hose at Summit Racing.
www.summitracing.com www.summitracing.com
I'm also thinking it would cut down on fittings as I could go straight from the fuel filter to the fuel pressure regulator (and regulator back to return port on the sending unit) in one run instead of having to plumb short runs of soft line to connect to the hard line at both ends.
 
StretchASU said:
I went back with hose when I redid the YJ a few months ago. One run, cut for filter fittings, pump fittings etc. Run it where you want and use cush clamps to secure to the tub/frame wherever it needs to go.
Click to expand...
I concur. Then as later mods happen you can easily move and adjust.
 
1st (GM) TBI iteration was FI-rated hose tank/filter/pump/filter and slightly modified GM factory hardlines/SS braided to TB, back thru the same for return
2nd (Sniper) TBI is all Holley supplied (Earl's VaporGuard) FI-rated hose stem to stern... with the overall plan to move to some sort of applicable braid in the future
 
New sending unit should be here tomorrow from MTS. This is the fuel pump I'm going to use that's compatible with the ProFlo ecu
www.summitracing.com

Summit Racing SUM-250103 Summit Racing™ In-Tank Fuel Pumps | Summit Racing

Free Shipping - Summit Racing™ In-Tank Fuel Pumps with qualifying orders of $109. Shop Fuel Pumps at Summit Racing.
www.summitracing.com www.summitracing.com

What else do I need to pick up from Summit to complete this swap?
A) I need to figure out how to pass the wiring through the sending unit

B) I need to modify the supply and return hardlines on the sending unit to accept the -6 hose in post #1
i) The OE supply is 5/16 and return is 1/4.
ii) My thought right now is to remove both hardlines from the sending unit and replace them with 3/8 hardlines and also extend the return further down into the sump to minimize foaming. I just don't know how feasible that actually is...
 
Talking to myself, but here is my plan:
-6 bulkhead fittings to go through the sending unit in the original tube locations. Supply side will use EFI hose from pump to bulkhead fitting, return side will use 3/8 steel tube. I will affix the pump to the return side using a clamp to stabilize the pump (similar to how the aftermarket guys do it).
I thought about just brazing 3/8 tube to the sending unit in the original tube locations, but got worried about over heating the electronics that are inside, or the weld cracking and failing.
Not gonna lie, I've also thought about just JB Welding the tube as well, but that feels .. less than good.

1727275613997.png
 
After looking at the sending unit, I don’t think there’s room for the AN bulkhead fittings. I’m back on the soldering 3/8 tubing in place of the existing supply and return tubes.

IMG_2196.jpeg

IMG_2198.jpeg

IMG_2204.jpeg

IMG_2206.jpeg
 
Cut the exterior end off the existing supply line, pick up a steel (weld on) male -6 AN fitting, and have someone TIG it on there. That'd be the easiest thing to do.

Inside: a couple of hose clamps and some submersion rated ⅜ fuel hose. Maybe add a slight flare for warm fuzzies, but make sure the hose will still go over it.

The return side should be fine as is, honestly. Plenty of factory setups use ⅜ feed and 5/16 returns. I'd imagine it would flow enough.
 
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Bebop said:
You can fuel up a 500hp LS engine with those hoses no problem.
Click to expand...
So based on that I could use the OE supply side (5/16) as the new return and just replace the OE return side (1/4) with a 3/8 line. That makes things a little easier.

I was planning 3/8 supply and return based on a Edelbrock's recommendation.
 
I see one single bulkhead pass through in your photo. How do you supply both power and ground?
 
Bebop said:
I see one single bulkhead pass through in your photo. How do you supply both power and ground?
Click to expand...
I was going to use one of these
www.summitracing.com

ATL Fuel Cells CFD-504 ATL Electrical Bulkhead Fittings | Summit Racing

Free Shipping - ATL Electrical Bulkhead Fittings with qualifying orders of $109. Shop Electrical Bulkhead Connectors at Summit Racing.
www.summitracing.com www.summitracing.com

Looks to be the same thing on McMaster

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com www.mcmaster.com
 
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I've had a bunch of meetings this week that definitely couldn't have been a simple email, so I've done a bit of googling and reading.
Over on FSJNetwork it seems most guys have been running the Novak EFI pump for LS conversions, which is just the stock replacement sending unit with an EFI pump attached to the 5/16 supply and utilizes the 1/4 return. The lazy POS in me is considering doing this
1728568795634.png



Another guy did similar to what I've been thinking about doing, and soldered on a 3/8 tub where the 1/4 return was.
1728568743149.png


This is probably what I'm going to do
 
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