76ford466
Another member
This my be a little long but it may help someone so here goes. I'm working on converting my 92 from a 460 to 7.3 idi. This leaves some different options on the fuel to engine part. Since I sold my Donal truck before I pulled the tanks I had nothing to go on. New diesel pickups and selector valve is very expensive. So I decided on using the stock in tank fi pumps figured a psi bypass regulator and I'd be good to go. It's not so easy. I got a Mallory three port by pass reg. plumbed it up to the 5/16 lines from stock then hoed onto the stock return to do a check. With the reg set to full bypass it held 4psi on the return way too much. Figured this was due to too small of a return. I started working on a 3/8 return into the top of the FDM, but I caught the plug on fire brazing in the line. Not a big deal as the pump was old and the float was bad. Purchased
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a new replacement pump. Put the return in top of the tank temporally to test it. After the new pump install I tried the lines out again stock return as a comparison. Well it blew my supply line off and pegged my gauge! I wondered why tried it with the new 3/8 return no residual psi on the line. I suspected a check valve of some sort in the return. They is I pulled the old FDM apart found a shuttle valve that requires x amount of psi on the supply side to open, this is how it selects the return to the correct tank, the old one was flat worn out and bypassing. So how do you now select the tanks use a standard fv-1 universal tank selector and another return line in the rear tank. This will work with the stock injection pump as the stock ford pump is rated at 33gph at 45psi, the gph will go up slightly with lower psi. Stock mechanical pump is rated for 36 gph. I will get another higher output pump after I get it running. Then I will switch to a external pump such as a fass. Already have my dual filters built and installed. Hope this helps someone.
