Fuel system questions

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Oct 28, 2020 | 04:12 AM

84_6.9

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Fuel system questions

Alright guys, more questions. Its much easier to ask here than hunt and peck on google.

My truck has no front tank under the bed. It disappeared long before I got it. PO put a 30 gallon transfer tank in the bed as the “front” tank.

The rear tank was upgraded some time ago to a 38 gallon unit. It’s old, and leaks somewhere when full. The return lines dump into the rear tank all the time. It’s amazing how long I can run on the rear tank, but the front one only lasts a few hours.

I have purchased Classic Diesel Designs bronco conversion rear tank. 38 gallon, sump, new sender, etc. My questions are:

1) is the sump on the bottom of the new tank a pump as well? If so, at what psi does it push fuel up?

2) are the fuel lines metal or rubber? Or does it matter in this scenario? I’m going to delete the bed tank and just run off the rear tank.

3) what pressure do the return lines run?

4) best filler neck setup?

i am seriously looking forward to not having a kaleidoscope of color on wet pavement behind the truck. Looking forward even more to having a proper fuel gauge.

Oct 28, 2020 | 05:42 AM

tjc transport

i ain't rite

Joined: Mar 2005

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From: Marlboro Mental Hospital.

no fuel pump in tank on an IDI.
fuel pressure on return is around 5-7 psi.
lines SHOULD BE steel with rubber connectors at tank.
best fill neck is factory.

Oct 28, 2020 | 06:26 AM

84_6.9

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Quote:

Originally Posted by tjc transport

no fuel pump in tank on an IDI.
fuel pressure on return is around 5-7 psi.
lines SHOULD BE steel with rubber connectors at tank.
best fill neck is factory.

Should be as in needs to be, or should be as in that’s what was factory, but high pressure rubber will work?

Trying to determine if I need to go on and order new fuel line and just bend and flare it to fit custom.

Oct 28, 2020 | 07:38 AM

tjc transport

i ain't rite

Joined: Mar 2005

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From: Marlboro Mental Hospital.

Should have been steel from factory.
no need for high pressure, the fuel system is a suction system.
return is low pressure system. With a max of around 7 psi

Oct 28, 2020 | 07:57 AM

84_6.9

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Quote:

Originally Posted by tjc transport

Should have been steel from factory.
no need for high pressure, the fuel system is a suction system.
return is low pressure system. With a max of around 7 psi

Okay, so just to make sure I have this right-

the sump is a gravity feed into the fuel line, not a pump out of the tank.

I can run rubber lines all the way from the tank to the mechanical pump on the side of the block with no issue. No need for high pressure even. The carter pump is what pulls fuel from the tanks, so there is no pump from the tank to the carter pump.

I hate not having answers when asked later by the guys helping me with this. They know cars, they just don’t know the bullnose IH.

Thanks again for all your help.