Dual tank diesel, where to put fuel pump?

[tundrawolf]

Hi,


I have an 84 k1500 with the 6.2 Diesel engine and dual tanks. Recently I've had a girl system issue with the introduction of air, and I am re-doing the entire system, as when I bought the truck it already had a "bubba" system on it (tiny plastic lift pump in the engine bay, etc...)

I have a fairly stout pump coming to me soon, rated at 160 gph and 10psi, but it was expensive.

I have the 6 port switching valve...

My issue is, I want to suck fuel directly from the tank with the lift pump, but I do not want to use two lift pumps, one for each tank.

I am slightly concerned the switching valve may be allowing air in? Outside of that my only other option is to use two lift pumps, and wire it to the switch somehow.

 

[Grit dog]

Put the pump as close upstream of the switching valve and as low vertically, as possible. Will work great there.
That’s where I relocated my bubba system too. And still running it off of a little Edelbrock in-line peanut pump.

 

[Ricko1966]

Well I'd want my pump as close to the tank and as low as possible. But evidently Chevrolet thought it was okay to put the lift pump for the 6.5 under the driver seat inside the frame rail. Also the GM pump is only 4 psi,I'd be nervous runni.g 10 and a factory 6.5 pump is dirt cheap,you might consider that.

 

[Rickf]

Or....solve any air intake issues and use a stock engine mounted pump. My old '84 C-10 6.2 with dual tanks had pin holes in both sending units. Replacing the sending units solved the sucking air problem.

 

[SquareRoot]

Will someone explain the "girl" and "bubba" system? I tried googling it and ended up on a forbidden website. Now I get to explain that to my boss and the IT folks.

 

[Ricko1966]

If I thought I was getting air somewhere I'd put that new pump at the back run 12v to it dead head it and look for fuel leaks

 

[backwoodsman]

If I thought I was getting air somewhere I'd put that new pump at the back run 12v to it dead head it and look for fuel leaks

That doesn't always work, especially if there's rubber fuel hose in the system. I've had rubber hose get porous to air when it gets old, so air gets sucked in right through it but fuel doesn't leak.

@tundrawolf That would be something to check if there's any old rubber fuel hose upstream of the fuel pump. Replace it and see what happens.

 

[Ricko1966]

Nothing works 100 percent,100 percent of the time but dead heading the pump if you do find leaks will save you a bunch of time.you know that just changing the rubber line doesn't always work either. And neither one of us may be right maybe he needs a sending unit,maybe he needs an injection pump. I'd still check for leaks.

 

[Albrigap]

My 82 6.2 had a lift pump on the engine that worked well for 1/4 million miles.
I modified the fuel gauges so I could see both tanks at all times but the switch still changed tank left or right.
I ran pure #1 in one tank and premium #2 in the other in the winter.
I gets ball bustin cold here.