Fuel line question(s)

[kc0stp]

Looking to add an electric fuel pump under the truck between the transfer case and front tank however Im not 100% sure on which line is supply vs return or best way to splice into them. (bottom line is brakes)

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[icanfixall]

Really can't tell you what line is supply by the pics but this I know for certain. The larger line is 3/8 inch and that the supply. The smaller line is 5/16 and thats the return line. Of course the hard line is brakes.

 

[kc0stp]

It looks like the top line is slightly larger but its close enough I wasn't sure (knew supply had to be bigger but...) any idea how to tap into the line?

 

[vegas39]

It looks like the top line is slightly larger but its close enough I wasn't sure (knew supply had to be bigger but...) any idea how to tap into the line?

Most of us just cut the plastic line and slide the new rubber fuel hose over it and clamp it. Mines been like that for 4 years and no problem.

 

[gandalf]

I too had to figure this one out when I put in the e-pump. My answer will be based on the attached picture of the FSV on my truck. Keep in mind, this is a '92 F-350. Other years may possibly be different, but I don't think they'll vary too much.

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Don't know why that got turned 90°. The top of the picture is toward the front of the truck, so bend your head to the left. IE, rotate the picture 90° clockwise.

That's the FSV, mounted on the frame rail, near the front fuel tank (you can see the corner of the tank). The two lines going forward are coming out the top of the FSV (to the left as the picture sits). The engine feed is the one closer to the frame, and the return is closer to the fuel tank. So, as they exit out the top of the picture, the return line is to the left, and the feed line is to the right.

If you pull those lines off the FSV, be sure to have some new clips on hand. You'll probably break the existing clip. Remember, pull the clip out, then pull the line off the FSV. The clips are Dorman part number 800-015.

If you need me to re-orient and/or label the picture, let me know.

Hope that helps.

Edit: I didn't realize, looking at the thumbnail picture, that I had labeled things. That may help too.

 

[kc0stp]

Finally found the FSV (hidden behind skid plate) and based on your drawing the top line in my pics is the feed line. Plain ole 3/8 rubber diesel line fit over the plastic line or need to go 1 size bigger?

 

[gandalf]

I really can't tell you whether the 3/8 rubber line will slip over the 3/8 plastic. I didn't do it that way. I have two entire systems parallel to each other. I left the original plastic line untouched, just disconnected at both ends. I ran 3/8 rubber directly off the FSV, all the way to the stock fuel filter. I have a Carrier pump and a GoldenRod filter along the way. If my Carrier pump craps out I can reconnect the stock system very easily.

If you want to cut the plastic line, I'd suggest perhaps getting a small sample of 3/8 rubber hose and seeing whether it will slip over.

 

[icanfixall]

I simpley cut the 3/8 plastic supply line and the new rubber hose fit over it easily. What was a problem is the fuel leaking out of the newly cut line. I installed the new lines on my new electric pump first. then cut out a section of plastic line to fit. No matter what you do diesel is going to spill down your arms and end up in your arm pits. Thats where it starts burning. See how fast you can get out from under the truck with the burn going on. This happened to me and now when I remove anything in the fuel system under the truck I place a 4 inch C clamp I have on the tank side of the system. Then the amount of fuel leak is much less even none at all because the fuel system is tight all the way to the injection pump.