When you upgrade the lift pump on the 2nd gen trucks I understand that you could simply connect the FASS, GDP, Walbro, MITUSA , etc pumps with the suction side connected to the factory fuel tank supply line. The 3rd gen trucks with the in-tank lift pump don’t allow the same approach. The practice is to drill a new hole in the top of the tank and install a “draw straw” fuel line into the tank. The problem arises when the tank is ¼ or less and acceleration or deceleration takes place. The new fuel suction line loses contact with the fuel causing pump cavation. There are various solutions I imagine, but I was considering this one based on a couple of assumptions. The 1st assumption is that I can somehow install the MITUSA pickup line in the factory pump assembly supply canister. The 2nd assumption is that my limited understanding of fluid dynamics allows the proposal to function as I imagine it would. And finally, that physical space and fitting availability permits the configuration. I know that MITUSA and GDP have you install a HOBBS switch to shut off the electric factory lift pump after the mechanical pump makes pressure. My setup would require the factory pump to run so that it draws fuel into the canister with less than a 1/4 tank. I was thinking that since the factory pump is designed to operate whenever the engine is running, running this pump whenever the engine is operational should fall within specs The factory lift pump is setup to actually draw fuel into a fuel bowl/canister and then pump it to the CP3. I was hoping to utilize the factory fuel pickup system to feed the MITUSA. My goal is to be able to operate at ¼ tank or less and prime the MITUSA with the electric in-tank pump. Does anyone see any issues I may have overlooked, or suggestions to achieve this goal easier? Thanks

 

Maybe the simplest and best thing would be to run the factory '03, '04 dip tube setup. These have no intank pump and will pick up almost all the fuel. I have put 39 gallons in mine while it was still running fine and the gauge had been pegged on empty for many miles. Or you could look at one and see how they are made. Might save a lot of hardware and fittings.

John

 

There has to be a way to gut the factory in-tank pump so an aftermarket pump can just hook up to the factory lines and pull fuel through the factory pickup. I'm surprised nobody has tried it yet.