Gas vs Diesel Gas Tank Sending Unit

[andyh1956]

All my 18 wheelers & diesel eqpt return fuel to the top of the tank.
Here's how to plumb this up with two tanks & not worry with the switching valve apparatus & you will only need one fuel level sender:
All new trucks are plumbed thusly-
One hose from the engine to a tee. From the tee equal length hose to each tank, this is for suction.
For the return from the engine to the return tee. This tee has two little "Flappers" in it that act as check valves & the return fuel has to reach a min "Cracking" pressure to open the flappers & continue on to the fuel tank. The hoses from the return tee to tank should be equal length also.
This way you will draw from both tanks & return to both tanks equally.
You are gonna have to fill both tanks independently anyway so why not design the system as simple as possible!
Any Navistar / Freightliner / Peterbuilt place or better yet LKQ yard will have these valves.

[RADustin]

the duramax ecm will run a transfer pump and merge the senders. So no fancy valves or plumbing is required. Just setup a primary tank, and a transfer pump on the secondary tank to pump in the first. The ECM handles the rest.

[andyh1956]

Originally Posted by RADustin

the duramax ecm will run a transfer pump and merge the senders. So no fancy valves or plumbing is required. Just setup a primary tank, and a transfer pump on the secondary tank to pump in the first. The ECM handles the rest.

What model Duramax are you referring to?
I am un-aware of this feature on '02 my LB7.
(Or at least I've never seen it while scanning)
That sure sounds handy!

[RADustin]

yep- function is used on cab chassis models with dual tanks.

[sweetk30]

and also dosnt start to transfer until the primary tank is at 3/4 or less .

just not sure if the ohm's range is the same as the older square body trucks senders tho . and the transfer pump is just that suction off the bottom of the 2nd tank sender to the primary tank via a frame rail mounted pump like a fuel fliter .

[RADustin]

Originally Posted by sweetk30

and also dosnt start to transfer until the primary tank is at 3/4 or less .

just not sure if the ohm's range is the same as the older square body trucks senders tho . and the transfer pump is just that suction off the bottom of the 2nd tank sender to the primary tank via a frame rail mounted pump like a fuel fliter .

Yep, all variables are tunable.

I have the LGH transfer pump already. Just need to mount and plumb.

[sweetk30]

i wish someone made a universal box to let us 2 tank guys have this option on our older trucks .

set the ohm's range of full / empty and then on/off spec for pumping .

[RADustin]

Remind me when I finish my build. I can whip something up.

[87max]

Happy to help.